EP1507017A1 - A method of heat treating titanium aluminide - Google Patents
A method of heat treating titanium aluminide Download PDFInfo
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- EP1507017A1 EP1507017A1 EP04254344A EP04254344A EP1507017A1 EP 1507017 A1 EP1507017 A1 EP 1507017A1 EP 04254344 A EP04254344 A EP 04254344A EP 04254344 A EP04254344 A EP 04254344A EP 1507017 A1 EP1507017 A1 EP 1507017A1
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- titanium aluminide
- temperature
- aluminide alloy
- alpha
- titanium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
- C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
- C22F1/16—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of other metals or alloys based thereon
- C22F1/18—High-melting or refractory metals or alloys based thereon
- C22F1/183—High-melting or refractory metals or alloys based thereon of titanium or alloys based thereon
Definitions
- the present invention relates to a method of heat-treating titanium aluminide and in particular to a method of heat-treating gamma titanium aluminide.
- Our European patent application no. 03253539.5 filed 4 June 2003 discloses a method of heat-treating a titanium aluminide alloy having a single alpha phase field and being capable of producing a massively transformed gamma microstructure.
- a method of heat-treating the titanium aluminide alloy is heated to a temperature above the alpha transus temperature, is maintained above the alpha transus temperature in the single alpha phase field for a predetermined time period, is cooled from the single alpha phase field to ambient temperature to produce a massively transformed gamma microstructure, is heated to a temperature below the alpha transus temperature in the alpha and gamma phase field, is maintained at the temperature below the alpha transus temperature for a predetermined time period to precipitate alpha plates in the massively transformed gamma microstructure such that a refined microstructure is produced and is then cooled to ambient temperature.
- a problem with this heat-treatment is that the cooling, quenching, of the titanium aluminide from above the alpha transus to ambient temperature induces quenching stresses in the titanium aluminide.
- a further problem is that the heat-treatment is only suitable for relatively thin castings.
- Another problem is that the heat-treatment is only applicable to compositions of titanium aluminide with a particular range of aluminium.
- the present invention seeks to provide a novel method of heat-treating titanium aluminide alloy which reduces, preferably overcomes, the above-mentioned problems.
- the present invention provides a method of heat-treating titanium aluminide alloy, the titanium aluminide alloy having a single alpha phase field and being capable of producing a massively transformed gamma microstructure, the method comprising the steps of :-
- the predetermined time period is up to 2 hours.
- the predetermined time period is up to 4 hours.
- step (e) comprises heating the titanium aluminide alloy to a temperature about 30°C to 60°C below the alpha transus temperature.
- step (a) comprises heating the titanium aluminide alloy to a temperature of about 20°C to 30°C above the alpha transus temperature.
- step (g) comprises air-cooling or furnace cooling.
- step (c) comprises fluidised bed cooling or salt bath cooling.
- titanium aluminide may be cooled to ambient temperature by air-cooling or oil cooling
- the titanium aluminide alloy may comprise 48at% aluminium, 2at% chromium, 2at% niobium and the balance titanium and incidental impurities.
- the alpha transus temperature is about 1360°C
- step (a) comprises heating to a temperature of 1380°C
- step (b) comprises maintaining the titanium aluminide alloy at a temperature of about 1380°C for about 1 hour
- step (c) and (d) comprise salt bath, or fluidised bed, cooling the titanium aluminide alloy from a temperature of 1380°C to a temperature between 900°C and 1200°C and maintaining the titanium aluminide alloy at the temperature in the range of 900°C to 1200°C for a predetermined time period to produce a massively transformed gamma microstructure
- steps (e) and (f) comprise heating the titanium aluminide alloy to a temperature of about 1320°C for about 2 hours to precipitate alpha plates in the massively transformed gamma microstructure such that a refined microstructure is produced in the titanium aluminide alloy
- step (g) comprises air cooling the titanium aluminide alloy to ambient temperature.
- the titanium aluminide alloy may comprise 46at% aluminium, 8at% niobium, up to 0.07at% carbon and the balance titanium and incidental impurities.
- the alpha transus temperature is about 1335°C
- step (a) comprises heating to a temperature of 1360°C
- step (b) comprises maintaining the titanium aluminide alloy at a temperature of about 1360°C for about 1 hour
- steps (c) and (d) comprise salt bath cooling, or fluidised bed cooling, the titanium aluminide alloy from a temperature of 1360°C to a temperature between 900°C and 1200°C and maintaining the titanium aluminide alloy at the temperature in the range of 900°C to 1200°C for a predetermined time period to produce a massively transformed gamma microstructure
- steps (e) and (f) comprise heating the titanium aluminide alloy to a temperature of about 1300°C to about 1320°C for about 4 hours to precipitate alpha plates in the massively transformed gamma microstructure such that a refined microstructure is produced in the titanium aluminide alloy
- step (g) comprises air cooling the titanium aluminide alloy to ambient temperature.
- the titanium aluminide alloy may consist of 45-46at% aluminium, 8at% niobium, up to 0.07at% carbon and the balance is titanium and incidental impurities.
- the titanium aluminide alloy may consist of 45-46at% aluminium, 2-6at% niobium, 2-6at% hafnium and the balance is titanium plus incidental impurities.
- the titanium aluminide alloy may be a cast titanium aluminide component.
- the method may comprise hot isostatic pressing of the cast titanium aluminide alloy component.
- step (f) Preferably the hot isostatic pressing of the cast titanium aluminide alloy component is concurrent with step (f).
- the hot isostatic pressing comprises applying a pressure of about 150MPa for about 4 hours.
- the titanium aluminide alloy may be a compressor blade or a compressor vane.
- a method of heat-treating a titanium aluminide alloy according to the present invention is described with reference to figure 1.
- the present invention is concerned with heat-treating gamma titanium aluminide alloys with at least 46at% aluminium and a single alpha phase field.
- the heat treatment process comprises heating the gamma titanium aluminide to a temperature T 1 above the alpha transus temperature T ⁇ .
- the gamma titanium aluminide alloy is then maintained at a temperature T 1 above the alpha transus temperature T ⁇ in the single alpha phase field for a predetermined time period t 1 .
- the gamma titanium aluminide is quenched, for example fluidised bed cooled, or slat bath cooled, from the single alpha phase field at temperature T 1 to a temperature T 2 .
- the gamma titanium aluminide alloy is maintained at temperature T 2 for a predetermined time period t 2 to produce a massively transformed gamma microstructure.
- the gamma titanium aluminide alloy is then heated to a temperature T 3 below the alpha transus temperature T ⁇ .
- the gamma titanium aluminide alloy is maintained at the temperature T 3 in the alpha and gamma phase field for a predetermined time period t 3 to precipitate alpha plates in the massively transformed gamma microstructure such that a refined microstructure is produced in the titanium aluminide alloy.
- the gamma titanium aluminide is cooled, for example air cooled, or furnace cooled, to ambient temperature.
- the gamma titanium aluminide is heated to a temperature T 1 about 20°C to 30°C above the alpha transus temperature T ⁇ .
- the gamma titanium aluminide alloy is maintained at the temperature T 1 for up to 2 hours.
- the gamma titanium aluminide alloy is then quenched, for example fluidised bed cooled, or salt bath cooled, to a temperature T 2 about 900°C to 1200°C and maintained for a predetermined time period to induce a massively transformed gamma microstructure.
- the gamma titanium alloy is heated to a temperature T 3 about 30°C to 60°C below the alpha transus temperature T ⁇ .
- the gamma titanium aluminide alloy is maintained at the temperature T 3 for up to 4 hours to precipitate fine alpha plates with different orientations in the massively transformed gamma microstructure due to the massive gamma to alpha + gamma phase transformation. This gives rise to a very fine duplex microstructure.
- the differently orientated alpha plates precipitated in the massive gamma phase matrix effectively reduce the grain size of the gamma titanium aluminide.
- the gamma titanium aluminide alloy is then cooled, for example air cooled, or furnace cooled, to ambient temperature.
- the holding at temperature T 1 for a time period t 1 also acts a homogenisation process for cast titanium aluminide alloys.
- a gamma titanium aluminide alloy consisting of 46at% aluminium, 8at% niobium, up to 0.07at% carbon and the balance titanium plus incidental impurities was heat treated according to the present invention.
- the gamma titanium aluminide alloy was fluidised bed, or salt bath, quenched to a temperature 900°C ⁇ T 2 ⁇ 1200°C and was held at temperature T 2 , where 900°C ⁇ T 2 ⁇ 1200°C, for a sufficient time to allow the massive transformation to go to completion.
- the gamma titanium aluminide alloy was air cooled to ambient temperature.
- the gamma titanium aluminide alloy is air-cooled or oil cooled from temperature T 2 to ambient temperature before the gamma titanium aluminide alloy is heated to the temperature T 3 .
- the present invention is applicable to a gamma titanium aluminide alloy consisting of 46at% aluminium, 5at% niobium, 0.3at% boron, 0.2at% carbon and the balance titanium plus incidental impurities.
- the present invention is applicable to a gamma titanium aluminide alloy consisting of 47at% aluminium, 2at% niobium, 1at% tungsten, 1at% chromium, 1at% boron, 0.2at% silicon and the balance titanium plus incidental impurities.
- the present invention is applicable to gamma titanium aluminide alloy consisting of 47at% aluminium, 2at% tantalum, 1at% chromium, 1at% manganese, 1at% boron, 0.2at% silicon and the balance titanium plus incidental impurities.
- the present invention is also applicable to gamma titanium aluminide alloy consisting of 46at% aluminium, 5at% niobium, 1at% tungsten and the balance titanium plus incidental impurities.
- the present invention is applicable to a gamma titanium aluminide alloy consisting of 45-46at% aluminium, 8at% niobium, up to 0.07at% carbon and the balance is titanium and incidental impurities.
- the present invention is also applicable to a gamma titanium aluminide alloy consisting of 45-46at% aluminium, 2-6at% niobium, 2-6at% hafnium and the balance is titanium plus incidental impurities.
- the present invention is also applicable to a gamma titanium aluminide alloy consisting of 48at% aluminium, 2at% chromium, 2at% niobium and the balance titanium and incidental impurities.
- the advantages of the present invention are that the cooling, quenching, of the titanium aluminide from above the alpha transus to an intermediate temperature induces reduced levels of quenching stresses compared to cooling, quenching, to ambient temperature as described in our European patent application no. 03253539.5.
- a further advantage is that at temperatures above about 1000°C the titanium aluminide is relatively ductile and the quenching stresses do not cause fracture.
- the heat-treatment is suitable for relatively thin castings and for larger castings so that they all have improved ductility and high strength. Also the heat-treatment is applicable to compositions of titanium aluminide with a broader range, a lower level, of aluminium and hence it is applicable to stronger titanium aluminide alloys.
- the lower level of aluminium may be 45at% and possibly 44at%.
- the present invention provides a heat treatment for gamma titanium aluminide alloy components, which provides grain refinement. It is particularly suitable for relatively large and complex shaped cast components where the previous heat treatment would induce high residual stresses and possibly cracking of the gamma titanium aluminide alloy components.
- the heat treatment also permits grain refinement throughout relatively large and complex shaped components rather than just the surface regions of the component.
- titanium aluminide alloy component may be heated to a temperature of about 1300°C and to maintain the titanium aluminide alloy component at about 1300°C to allow the temperature to equilibrate in the titanium aluminide alloy component so that the titanium aluminide alloy component needs to be maintained at temperature T 1 for a shorter time period.
- the cast gamma titanium aluminide alloy component may be hot isostatically pressed (HIP) to remove the porosity.
- the hot isostatic pressing preferably occurs at the same time as the heat treatment temperature T 2 and for the time period of about 4 hours at a pressure of about 150MPa and this is beneficial because this dispenses with the requirement for a separate hot isostatic pressing step.
- the present invention is particularly suitable for gamma titanium aluminide gas turbine engine compressor blades as illustrated in figure 2.
- the compressor blade 10 comprises a root 12, a shank 14, a platform 16 and an aerofoil 18.
- the present invention is also suitable for gamma titanium aluminide gas turbine engine compressor vanes or other gamma titanium aluminide gas turbine engine components.
- the present invention may also be suitable for gamma titanium aluminide components for other engine, machines or applications.
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Abstract
A gamma titanium aluminide alloy consisting of 46at% aluminium, 8at% niobium, up to 0.07at% carbon and the balance titanium plus incidental impurities has an alpha transus temperature T alpha = 1335 DEG C. The gamma titanium aluminide alloy was heated to a temperature T1 = 1360 DEG C and was held at T1 = 1360 DEG C for 1 hour or longer. The gamma titanium aluminide alloy was fluidised bed, or salt bath, quenched to a temperature T2, where 900 DEG C < T2 < 1200 DEG C, and was held at temperature T2 for a sufficient time to allow the massive transformation to go to completion. The gamma titanium aluminide alloy was heated to a temperature T3 = 1300 DEG C or 1320 DEG C and was held at T2 for 4 hours. The gamma titanium aluminide alloy was air cooled to ambient temperature. The gamma titanium aluminide alloy has a fine duplex microstructure comprising differently orientated alpha plates in a massively transformed gamma matrix. The heat treatment reduces quenching stresses, allows larger castings and a broader range of titanium aluminide alloys to be grain refined. <IMAGE>
Description
The present invention relates to a method of heat-treating
titanium aluminide and in particular to a method
of heat-treating gamma titanium aluminide.
There is a requirement to refine the microstructure of
a titanium aluminide alloy, in particular cast titanium
aluminide alloy, which does not involve hot working of the
titanium aluminide alloy.
Our European patent application no. 03253539.5 filed 4
June 2003 discloses a method of heat-treating a titanium
aluminide alloy having a single alpha phase field and being
capable of producing a massively transformed gamma
microstructure. In that method of heat-treating the
titanium aluminide alloy is heated to a temperature above
the alpha transus temperature, is maintained above the
alpha transus temperature in the single alpha phase field
for a predetermined time period, is cooled from the single
alpha phase field to ambient temperature to produce a
massively transformed gamma microstructure, is heated to a
temperature below the alpha transus temperature in the
alpha and gamma phase field, is maintained at the
temperature below the alpha transus temperature for a
predetermined time period to precipitate alpha plates in
the massively transformed gamma microstructure such that a
refined microstructure is produced and is then cooled to
ambient temperature.
A problem with this heat-treatment is that the
cooling, quenching, of the titanium aluminide from above
the alpha transus to ambient temperature induces quenching
stresses in the titanium aluminide. A further problem is
that the heat-treatment is only suitable for relatively
thin castings. Another problem is that the heat-treatment
is only applicable to compositions of titanium aluminide
with a particular range of aluminium.
Accordingly the present invention seeks to provide a
novel method of heat-treating titanium aluminide alloy
which reduces, preferably overcomes, the above-mentioned
problems.
Accordingly the present invention provides a method of
heat-treating titanium aluminide alloy, the titanium
aluminide alloy having a single alpha phase field and being
capable of producing a massively transformed gamma
microstructure, the method comprising the steps of :-
Preferably in step (b) the predetermined time period
is up to 2 hours.
Preferably in step (f) the predetermined time period
is up to 4 hours.
Preferably step (e) comprises heating the titanium
aluminide alloy to a temperature about 30°C to 60°C below
the alpha transus temperature.
Preferably step (a) comprises heating the titanium
aluminide alloy to a temperature of about 20°C to 30°C above
the alpha transus temperature.
Preferably step (g) comprises air-cooling or furnace
cooling.
Preferably step (c) comprises fluidised bed cooling or
salt bath cooling.
It may be possible to cool the titanium aluminide to
ambient temperature after step (d) and before step (e).
The titanium aluminide may be cooled to ambient temperature
by air-cooling or oil cooling
The titanium aluminide alloy may comprise 48at%
aluminium, 2at% chromium, 2at% niobium and the balance
titanium and incidental impurities.
The alpha transus temperature is about 1360°C, step (a)
comprises heating to a temperature of 1380°C, step (b)
comprises maintaining the titanium aluminide alloy at a
temperature of about 1380°C for about 1 hour, step (c) and
(d) comprise salt bath, or fluidised bed, cooling the
titanium aluminide alloy from a temperature of 1380°C to a
temperature between 900°C and 1200°C and maintaining the
titanium aluminide alloy at the temperature in the range of
900°C to 1200°C for a predetermined time period to produce a
massively transformed gamma microstructure, steps (e) and
(f) comprise heating the titanium aluminide alloy to a
temperature of about 1320°C for about 2 hours to precipitate
alpha plates in the massively transformed gamma
microstructure such that a refined microstructure is
produced in the titanium aluminide alloy, and step (g)
comprises air cooling the titanium aluminide alloy to
ambient temperature.
The titanium aluminide alloy may comprise 46at%
aluminium, 8at% niobium, up to 0.07at% carbon and the
balance titanium and incidental impurities.
The alpha transus temperature is about 1335°C, step (a)
comprises heating to a temperature of 1360°C, step (b)
comprises maintaining the titanium aluminide alloy at a
temperature of about 1360°C for about 1 hour, steps (c) and
(d) comprise salt bath cooling, or fluidised bed cooling,
the titanium aluminide alloy from a temperature of 1360°C to
a temperature between 900°C and 1200°C and maintaining the
titanium aluminide alloy at the temperature in the range of
900°C to 1200°C for a predetermined time period to produce a
massively transformed gamma microstructure, steps (e) and
(f) comprise heating the titanium aluminide alloy to a
temperature of about 1300°C to about 1320°C for about 4
hours to precipitate alpha plates in the massively
transformed gamma microstructure such that a refined
microstructure is produced in the titanium aluminide alloy,
and step (g) comprises air cooling the titanium aluminide
alloy to ambient temperature.
The titanium aluminide alloy may consist of 45-46at%
aluminium, 8at% niobium, up to 0.07at% carbon and the
balance is titanium and incidental impurities.
The titanium aluminide alloy may consist of 45-46at%
aluminium, 2-6at% niobium, 2-6at% hafnium and the balance
is titanium plus incidental impurities.
The titanium aluminide alloy may be a cast titanium
aluminide component.
The method may comprise hot isostatic pressing of the
cast titanium aluminide alloy component.
Preferably the hot isostatic pressing of the cast
titanium aluminide alloy component is concurrent with step
(f).
Preferably the hot isostatic pressing comprises
applying a pressure of about 150MPa for about 4 hours.
The titanium aluminide alloy may be a compressor blade
or a compressor vane.
The present invention will be more fully described by
way of example with reference to the accompanying drawings
in which:-
A method of heat-treating a titanium aluminide alloy
according to the present invention is described with
reference to figure 1. The present invention is concerned
with heat-treating gamma titanium aluminide alloys with at
least 46at% aluminium and a single alpha phase field.
The heat treatment process comprises heating the gamma
titanium aluminide to a temperature T1 above the alpha
transus temperature Tα. The gamma titanium aluminide alloy
is then maintained at a temperature T1 above the alpha
transus temperature Tα in the single alpha phase field for
a predetermined time period t1. The gamma titanium
aluminide is quenched, for example fluidised bed cooled, or
slat bath cooled, from the single alpha phase field at
temperature T1 to a temperature T2. The gamma titanium
aluminide alloy is maintained at temperature T2 for a
predetermined time period t2 to produce a massively
transformed gamma microstructure. The gamma titanium
aluminide alloy is then heated to a temperature T3 below the
alpha transus temperature Tα. The gamma titanium aluminide
alloy is maintained at the temperature T3 in the alpha and
gamma phase field for a predetermined time period t3 to
precipitate alpha plates in the massively transformed gamma
microstructure such that a refined microstructure is
produced in the titanium aluminide alloy. The gamma
titanium aluminide is cooled, for example air cooled, or
furnace cooled, to ambient temperature.
In particular, the gamma titanium aluminide is heated
to a temperature T1 about 20°C to 30°C above the alpha
transus temperature Tα. The gamma titanium aluminide alloy
is maintained at the temperature T1 for up to 2 hours. The
gamma titanium aluminide alloy is then quenched, for
example fluidised bed cooled, or salt bath cooled, to a
temperature T2 about 900°C to 1200°C and maintained for a
predetermined time period to induce a massively transformed
gamma microstructure. The gamma titanium alloy is heated
to a temperature T3 about 30°C to 60°C below the alpha
transus temperature Tα. The gamma titanium aluminide alloy
is maintained at the temperature T3 for up to 4 hours to
precipitate fine alpha plates with different orientations
in the massively transformed gamma microstructure due to
the massive gamma to alpha + gamma phase transformation.
This gives rise to a very fine duplex microstructure. The
differently orientated alpha plates precipitated in the
massive gamma phase matrix effectively reduce the grain
size of the gamma titanium aluminide. The gamma titanium
aluminide alloy is then cooled, for example air cooled, or
furnace cooled, to ambient temperature.
The holding at temperature T1 for a time period t1 also
acts a homogenisation process for cast titanium aluminide
alloys.
A gamma titanium aluminide alloy consisting of 46at%
aluminium, 8at% niobium, up to 0.07at% carbon and the
balance titanium plus incidental impurities was heat
treated according to the present invention. This gamma
titanium aluminide alloy has an alpha transus temperature
Tα = 1335°C. The gamma titanium aluminide alloy was heated
to a temperature T1 = 1360°C and was held at T1 = 1360°C for
1 hour for small components and longer for larger
components. The gamma titanium aluminide alloy was
fluidised bed, or salt bath, quenched to a temperature 900°C
< T2 < 1200°C and was held at temperature T2, where 900°C <
T2 < 1200°C, for a sufficient time to allow the massive
transformation to go to completion. The gamma titanium
aluminide alloy was heated to a temperature T3 = 1300°C or
1320°C and was held at T2 = 1300°C or 1320°C for 4 hours.
The gamma titanium aluminide alloy was air cooled to
ambient temperature.
As an alternative the gamma titanium aluminide alloy
is air-cooled or oil cooled from temperature T2 to ambient
temperature before the gamma titanium aluminide alloy is
heated to the temperature T3.
The present invention is applicable to a gamma
titanium aluminide alloy consisting of 46at% aluminium,
5at% niobium, 0.3at% boron, 0.2at% carbon and the balance
titanium plus incidental impurities. The present invention
is applicable to a gamma titanium aluminide alloy
consisting of 47at% aluminium, 2at% niobium, 1at% tungsten,
1at% chromium, 1at% boron, 0.2at% silicon and the balance
titanium plus incidental impurities. The present invention
is applicable to gamma titanium aluminide alloy consisting
of 47at% aluminium, 2at% tantalum, 1at% chromium, 1at%
manganese, 1at% boron, 0.2at% silicon and the balance
titanium plus incidental impurities. The present invention
is also applicable to gamma titanium aluminide alloy
consisting of 46at% aluminium, 5at% niobium, 1at% tungsten
and the balance titanium plus incidental impurities. The
present invention is applicable to a gamma titanium
aluminide alloy consisting of 45-46at% aluminium, 8at%
niobium, up to 0.07at% carbon and the balance is titanium
and incidental impurities. The present invention is also
applicable to a gamma titanium aluminide alloy consisting
of 45-46at% aluminium, 2-6at% niobium, 2-6at% hafnium and
the balance is titanium plus incidental impurities. The
present invention is also applicable to a gamma titanium
aluminide alloy consisting of 48at% aluminium, 2at%
chromium, 2at% niobium and the balance titanium and
incidental impurities.
The advantages of the present invention are that the
cooling, quenching, of the titanium aluminide from above
the alpha transus to an intermediate temperature induces
reduced levels of quenching stresses compared to cooling,
quenching, to ambient temperature as described in our
European patent application no. 03253539.5. A further
advantage is that at temperatures above about 1000°C the
titanium aluminide is relatively ductile and the quenching
stresses do not cause fracture. Another advantage is that
the heat-treatment is suitable for relatively thin castings
and for larger castings so that they all have improved
ductility and high strength. Also the heat-treatment is
applicable to compositions of titanium aluminide with a
broader range, a lower level, of aluminium and hence it is
applicable to stronger titanium aluminide alloys. It is
believed that the lower level of aluminium may be 45at% and
possibly 44at%. Thus, the present invention provides a
heat treatment for gamma titanium aluminide alloy
components, which provides grain refinement. It is
particularly suitable for relatively large and complex
shaped cast components where the previous heat treatment
would induce high residual stresses and possibly cracking
of the gamma titanium aluminide alloy components. The heat
treatment also permits grain refinement throughout
relatively large and complex shaped components rather than
just the surface regions of the component.
It may be possible to heat the titanium aluminide
alloy component to a temperature of about 1300°C and to
maintain the titanium aluminide alloy component at about
1300°C to allow the temperature to equilibrate in the
titanium aluminide alloy component so that the titanium
aluminide alloy component needs to be maintained at
temperature T1 for a shorter time period.
In the case of cast gamma titanium aluminide alloy
components it may be necessary to remove porosity from the
cast gamma titanium aluminide alloy component. In this
case the cast gamma titanium aluminide alloy component may
be hot isostatically pressed (HIP) to remove the porosity.
The hot isostatic pressing preferably occurs at the same
time as the heat treatment temperature T2 and for the time
period of about 4 hours at a pressure of about 150MPa and
this is beneficial because this dispenses with the
requirement for a separate hot isostatic pressing step.
The present invention is particularly suitable for
gamma titanium aluminide gas turbine engine compressor
blades as illustrated in figure 2. The compressor blade 10
comprises a root 12, a shank 14, a platform 16 and an
aerofoil 18. The present invention is also suitable for
gamma titanium aluminide gas turbine engine compressor
vanes or other gamma titanium aluminide gas turbine engine
components. The present invention may also be suitable for
gamma titanium aluminide components for other engine,
machines or applications.
Claims (20)
- A method of heat-treating titanium aluminide alloy, the titanium aluminide alloy having a single alpha phase field and being capable of producing a massively transformed gamma microstructure, the method comprising the steps of :-(a) heating a titanium aluminide alloy to a temperature (T1) above the alpha transus temperature (T∝),(b) maintaining the titanium aluminide alloy at a temperature (T1) above the alpha transus temperature in the single alpha phase field for a predetermined time period (t1),(c) cooling the titanium aluminide alloy from the single alpha phase field to a temperature (T2) in the range of 900°C to 1200°C,(d) maintaining the titanium aluminide alloy at the temperature (T2) in the range of 900°C to 1200°C for a predetermined time period (t2) to produce a massively transformed gamma microstructure,(e) heating the titanium aluminide alloy to a temperature (T3) below the alpha transus temperature in the alpha and gamma phase field,(f) maintaining the titanium aluminide alloy at the temperature (T3) below the alpha transus temperature for a predetermined time period (t3) to precipitate alpha plates in the massively transformed gamma microstructure such that a refined microstructure is produced in the titanium aluminide alloy,(g) cooling the titanium aluminide alloy to ambient temperature.
- A method as claimed in claim 1 wherein in step (b) the predetermined time period (t1) is up to 2 hours.
- A method as claimed in claim 1 or claim 2 wherein in step (f) the predetermined time period (t3) is up to 4 hours.
- A method as claimed in claim 1, claim 2 or claim 3 wherein step (e) comprises heating the titanium aluminide alloy to a temperature (T3) about 30°C to 60°C below the alpha transus temperature.
- A method as claimed in any of claims 1 to 4 wherein step (a) comprises heating the titanium aluminide alloy to a temperature (T1) of about 20°C to 30°C above the alpha transus temperature.
- A method as claimed in any of claims 1 to 5 wherein step (g) comprises air-cooling or furnace cooling.
- A method as claimed in any of claims 1 to 6 wherein step (c) comprises fluidised bed (FB) cooling or salt bath (SB) cooling.
- A method as claimed in any of claims 1 to 7 comprising cooling the titanium aluminide to ambient temperature after step (d) and before step (e).
- A method as claimed in claim 8 wherein the titanium aluminide is cooled to ambient temperature by air-cooling (AC) or oil cooling (OC).
- A method as claimed in any of claims 1 to 9 wherein the titanium aluminide alloy comprises 48at% aluminium, 2at% chromium, 2at% niobium and the balance titanium and incidental impurities.
- A method as claimed in claim 10 wherein the alpha transus temperature (T∝) is about 1360°C, step (a) comprises heating to a temperature (T1) of 1380°C, step (b) comprises maintaining the titanium aluminide alloy at a temperature (T1) of about 1380°C for about 1 hour, step (c) and (d) comprise salt bath (SB), or fluidised bed (FB), cooling the titanium aluminide alloy from a temperature (T1) of 1380°C to a temperature (T2) between 900°C and 1200°C and maintaining the titanium aluminide alloy at the temperature (T2) in the range of 900°C to 1200°C for a predetermined time period (t2) to produce a massively transformed gamma microstructure, steps (e) and (f) comprise heating the titanium aluminide alloy to a temperature (T3) of about 1320°C for about 2 hours to precipitate alpha plates in the massively transformed gamma microstructure such that a refined microstructure is produced in the titanium aluminide alloy, and step (g) comprises air cooling the titanium aluminide alloy to ambient temperature.
- A method as claimed in any of claims 1 to 9 wherein the titanium aluminide alloy comprises 46at% aluminium, 8at% niobium, up to 0.07at% carbon and the balance titanium and incidental impurities.
- A method as claimed in claim 12 wherein the alpha transus temperature (T∝) is about 1335°C, step (a) comprises heating to a temperature (T1) of 1360°C, step (b) comprises maintaining the titanium aluminide alloy at a temperature (T1) of about 1360°C for about 1 hour, steps (c) and (d) comprise salt bath (SB) cooling, or fluidised bed (FB) cooling, the titanium aluminide alloy from a temperature (T1) of 1360°C to a temperature (T2) between 900°C and 1200°C and maintaining the titanium aluminide alloy at the temperature (T2) in the range of 900°C to 1200°C for a predetermined time period (t2) to produce a massively transformed gamma microstructure, steps (e) and (f) comprise heating the titanium aluminide alloy to a temperature (T3) of about 1300°C to about 1320°C for about 4 hours to precipitate alpha plates in the massively transformed gamma microstructure such that a refined microstructure is produced in the titanium aluminide alloy, and step (f) comprises air cooling the titanium aluminide alloy to ambient temperature.
- A method as claimed in any of claims 1 to 9 wherein the titanium aluminide alloy consists of 45-46at% aluminium, 8at% niobium, up to 0.07at% carbon and the balance is titanium and incidental impurities.
- A method as claimed in any of claims 1 to 9 wherein the titanium aluminide alloy consists of 45-46at% aluminium, 2-6at% niobium, 2-6at% hafnium and the balance is titanium plus incidental impurities.
- A method as claimed in any of claims 1 to 15 wherein the titanium aluminide alloy is a cast titanium aluminide component.
- A method as claimed in any of claims 1 to 16 wherein comprising hot isostatic pressing of the cast titanium aluminide alloy component.
- A method as claimed in claim 17 wherein the hot isostatic pressing of the cast titanium aluminide alloy component is concurrent with step (f).
- A method as claimed in claim 17 or claim 18 wherein the hot isostatic pressing comprises applying a pressure of about 150MPa for about 4 hours.
- A method as claimed in any of claims 1 to 19 wherein the titanium aluminide alloy is a compressor blade (10) or a compressor vane.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0319061 | 2003-08-14 | ||
| GBGB0319061.8A GB0319061D0 (en) | 2003-08-14 | 2003-08-14 | A method of heat treating titanium aluminide |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| EP1507017A1 true EP1507017A1 (en) | 2005-02-16 |
Family
ID=28052473
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP04254344A Withdrawn EP1507017A1 (en) | 2003-08-14 | 2004-07-21 | A method of heat treating titanium aluminide |
Country Status (3)
| Country | Link |
|---|---|
| US (1) | US20050081967A1 (en) |
| EP (1) | EP1507017A1 (en) |
| GB (1) | GB0319061D0 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1813691A1 (en) * | 2006-01-27 | 2007-08-01 | Rolls-Royce plc | A method of heat treating titanium aluminide |
| EP1889939A3 (en) * | 2006-08-19 | 2008-10-29 | Rolls-Royce plc | An alloy and method of treating titanium aluminide |
| CN105039886A (en) * | 2015-08-05 | 2015-11-11 | 西部超导材料科技股份有限公司 | Method for preparing Zr-2.5Nb alloy rod with uniform small structure phase |
| EP3360983A1 (en) * | 2017-02-14 | 2018-08-15 | General Electric Company | Titanium aluminide alloys and turbine components |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2503738C2 (en) * | 2012-03-02 | 2014-01-10 | Федеральное государственное бюджетное учреждение науки Институт проблем сверхпластичности металлов Российской академии наук (ИПСМ РАН) | METHOD OF THERMAL TREATMENT OF CAST SLABS FROM HYPEREUTECTIC INTERMETALLIDE ALLOYS BASED ON PHASES γ-TiAl+α2-Ti3Al |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5205875A (en) * | 1991-12-02 | 1993-04-27 | General Electric Company | Wrought gamma titanium aluminide alloys modified by chromium, boron, and nionium |
| JPH06116691A (en) * | 1992-10-05 | 1994-04-26 | Mitsubishi Materials Corp | TiAl intermetallic compound Ti alloy heat treatment method |
| EP1308529A1 (en) * | 2001-11-05 | 2003-05-07 | Mitsubishi Heavy Industries, Ltd. | Titanium aluminum intermetallic compound based alloy and method of fabricating a product from the alloy |
| EP1378582A1 (en) * | 2002-07-05 | 2004-01-07 | ROLLS-ROYCE plc | A method of heat treating titanium aluminide |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4208485C2 (en) * | 1992-03-17 | 1997-09-04 | Wuenning Joachim | Method and device for quenching metallic workpieces |
| US5634992A (en) * | 1994-06-20 | 1997-06-03 | General Electric Company | Method for heat treating gamma titanium aluminide alloys |
| US6231699B1 (en) * | 1994-06-20 | 2001-05-15 | General Electric Company | Heat treatment of gamma titanium aluminide alloys |
| US5558729A (en) * | 1995-01-27 | 1996-09-24 | The United States Of America As Represented By The Secretary Of The Air Force | Method to produce gamma titanium aluminide articles having improved properties |
| USH1659H (en) * | 1995-05-08 | 1997-07-01 | The United States Of America As Represented By The Secretary Of The Air Force | Method for heat treating titanium aluminide alloys |
| US5653828A (en) * | 1995-10-26 | 1997-08-05 | National Research Council Of Canada | Method to procuce fine-grained lamellar microstructures in gamma titanium aluminides |
-
2003
- 2003-08-14 GB GBGB0319061.8A patent/GB0319061D0/en not_active Ceased
-
2004
- 2004-07-21 EP EP04254344A patent/EP1507017A1/en not_active Withdrawn
- 2004-08-09 US US10/913,528 patent/US20050081967A1/en not_active Abandoned
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5205875A (en) * | 1991-12-02 | 1993-04-27 | General Electric Company | Wrought gamma titanium aluminide alloys modified by chromium, boron, and nionium |
| JPH06116691A (en) * | 1992-10-05 | 1994-04-26 | Mitsubishi Materials Corp | TiAl intermetallic compound Ti alloy heat treatment method |
| EP1308529A1 (en) * | 2001-11-05 | 2003-05-07 | Mitsubishi Heavy Industries, Ltd. | Titanium aluminum intermetallic compound based alloy and method of fabricating a product from the alloy |
| EP1378582A1 (en) * | 2002-07-05 | 2004-01-07 | ROLLS-ROYCE plc | A method of heat treating titanium aluminide |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1813691A1 (en) * | 2006-01-27 | 2007-08-01 | Rolls-Royce plc | A method of heat treating titanium aluminide |
| US7704339B2 (en) | 2006-01-27 | 2010-04-27 | Rolls-Royce Plc | Method of heat treating titanium aluminide |
| EP1889939A3 (en) * | 2006-08-19 | 2008-10-29 | Rolls-Royce plc | An alloy and method of treating titanium aluminide |
| CN105039886A (en) * | 2015-08-05 | 2015-11-11 | 西部超导材料科技股份有限公司 | Method for preparing Zr-2.5Nb alloy rod with uniform small structure phase |
| CN105039886B (en) * | 2015-08-05 | 2017-02-01 | 西部超导材料科技股份有限公司 | Method for preparing Zr-2.5Nb alloy rod with uniform small structure phase |
| EP3360983A1 (en) * | 2017-02-14 | 2018-08-15 | General Electric Company | Titanium aluminide alloys and turbine components |
Also Published As
| Publication number | Publication date |
|---|---|
| GB0319061D0 (en) | 2003-09-17 |
| US20050081967A1 (en) | 2005-04-21 |
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