SU796706A1

SU796706A1 - Method of determining fracture viscosity of materials

Info

Publication number: SU796706A1
Application number: SU772487033A
Authority: SU
Inventors: Владислав Михайлович Аваев; Сергей Владимирович Журавлев
Original assignee: Предприятие П/Я М-5671
Priority date: 1977-05-19
Filing date: 1977-05-19
Publication date: 1981-01-15

Description

Изобретение относится к определению механических свойств материалов, в частности к способам определения ‘вязкости разрушения материалов.The invention relates to the determination of the mechanical properties of materials, in particular to methods for determining ‘fracture toughness of materials.

Известен способ определения вязкости разрушения материалов, заключающийся в том, что нагружают .образец материала с концентратом напряжений и наведенной трещеной, регистрируют нагрузку и длину трещины, по изменению которых судят о вязкости разрушения [1] .A known method for determining the fracture toughness of materials, which consists in loading a sample of material with a stress concentrate and induced crack, record the load and length of the crack, the change of which is used to judge the fracture toughness [1].

Недостатком данного способа является его низкая точность, поскольку имеется большой разброс механических свойств и структуры материала.The disadvantage of this method is its low accuracy, since there is a wide variation in the mechanical properties and structure of the material.

Цель изобретения повышение точности определения.The purpose of the invention is improving the accuracy of determination.

Указанная цель достигается тем, что дополнительно определяют предел текучести и структуру материала в месте страгивания трещины.This goal is achieved by the fact that they additionally determine the yield strength and structure of the material at the point of crack fracture.

Способ осуществляется следующим образом.The method is as follows.

Образы материала, изготовленные из этой заготовки, испытывают на вязкость разрушения. Для этого в образце выполняют концентратор напряжения и наводят из вершины концентратора трещину, на⁵ пример, усталостную. Затем нагружают образец, регистрируют нагрузки и дли- ны трещины, а также место страгивания трещины, соответствующее началу ее лавинообразного движения. По результатам испытания определяют величину К/_с~ вязкость разрушения. На частях ιразрушенного образца определяют предел G,_Tтекучести методом вдавливания жесткого ₎₅ конического наконечника, и средний поперечный размер d зерна, например, методом секущей на металлографических шлифах. Затем проводят корректировку значений вязкости разрушения для раз2jj личных образцов, например, находя отношение K_lC/Q_rVdT . В этом случае разброс результатов испытания уменьшается, например, для титановых сплавов более, чем в 2,4 раза.Material images made from this preform are tested for fracture toughness. To do this, a stress concentrator is performed in the sample and a crack is imposed from the top of the concentrator, for example, ⁵ fatigue. Then the specimen is loaded, the loads and lengths of the crack are recorded, as well as the place of crack cracking, corresponding to the beginning of its avalanche-like motion. The test results determine the value of K / _s ~ fracture toughness. On parts of the fractured specimen, the yield strength G, _T is determined by the method of pressing a hard _{) 5} conical tip, and the average transverse grain size d, for example, by secant method on metallographic thin sections. Then, the fracture toughness values are adjusted for various samples, for example, by finding the ratio K _lC / Q _r VdT. In this case, the spread of the test results decreases, for example, for titanium alloys by more than 2.4 times.

Claims

The invention relates to the determination of the mechanical properties of materials, in particular, to methods for determining the spine. destruction of materials. A known method for determining the fracture toughness of materials, which consists in loading a sample of a material with a stress concentrate and induced cracked, records the load and crack length, by changing which the fracture toughness is judged. The disadvantage of this method is its low accuracy, because it has a large spread of mechanical properties and structure of the material. The purpose of the invention is improving the accuracy of determination. This goal is achieved by additionally determining the yield strength and the structure of the material at the site of the crack initiation. The method is carried out as follows. Material images made from this preform are subjected to viscosity, fracture. To do this, a stress concentrator is made in the sample and a crack, such as a fatigue crack, is induced from the top of the concentrator. Then the sample is loaded, loads and lengths of the crack are recorded, as well as the place where the crack has started to move, corresponding to the beginning of its avalanche movement. Based on the test results, the K / "fracture viscosity" value is determined. In parts: of the destroyed specimen, the limit of G, the yield strength by the indentation of a rigid conical tip, and the average transverse dimension d of the grain are determined, for example, by the method of cutting on metallographic sections. Then, the fracture toughness values are adjusted for different samples, for example, finding the ratio S in this case, the spread of test results decreases, for example, for titanium alloys by more than 2.4 times. / -. . , 3 79670 Claims of Invention A method for determining the fracture toughness of materials, namely, loading a sample of material with a c5 stress concentrate and an induced crack, records the load and the length of the crack, by changing which the fracture viscosity is judged, which is only , in order to improve the determination accuracy, the yield strength and the structure of the material at the site of the emergency location are additionally determined. Sources of information taken into account for the examination 1. Curr suture - B. G. et al. The fracture toughness of aluminum alloys. Moscow, Metallurgists, 1976, p. 147-148 (prototype).