Method for estimating plane-strain fracture toughness of metal material

Abstract

The invention discloses a method for estimating plane-strain fracture toughness of a metal material, and belongs to the technical field of fracture toughness of metal materials. The method comprises three steps: performing a fracture toughness experiment on a small sample to obtain an experimental value Kq, performing linear fitting on Kq2B and specimen thickness B and performing accurate calculation through straight line slope to obtain KIC. According to the method, the plane-strain fracture toughness of the material can be measured simply and effectively, so that the experiment cost is greatly reduced; in addition, as the KIC of materials (such as amorphous alloys or nano-metal materials) cannot be measured due to a preparation process or relatively high toughness of the materials, accurate parameters can be provided through the method, so that a strong basis is provided for material selection, and particularly, a theoretical basis is provided for the damage tolerance design of a component of the aviation manufacturing industry.

Description

Technical field: [0001] The invention relates to the technical field of fracture toughness of metal materials, in particular to a method for estimating plane strain fracture toughness of metal materials. Background technique: [0002] With the continuous progress and development of modern science and technology, all walks of life have increasingly higher requirements for the mechanical properties of structural materials, and high strength and high toughness have become the development direction of structural materials. In particular, fracture toughness is used as an important index to measure materials in important fields such as aerospace, nuclear power plants, and oil pipelines [Cao Chunxiao. Changes in material selection criteria and the development of high damage-tolerant titanium alloys, Acta Metall Sinica, 2002, 38: 4 -11.]. Fracture toughness is a parameter of a material's ability to resist crack instability, and its theoretical basis is fracture mechanics. Fracture...

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Problems solved by technology

Gludovatz et al. studied the fracture toughness of small samples in amorphous metals. They believed that the fracture toughness of small samples in amorphous metals may also be consistent with the American standard ASTM. Of course, the article also pointed out that the fracture toughness of small samples exists. Disadvantage of large dispersion [Gludovatz B, Naleway S E, Ritchie R O, et al. Size-dependent fracture toughness of bulk metallic glasses [J]. Acta Materialia, 2014, 70: 198-207.]

Generally speaking, although many scholars have done a lot of work on how to use small samples or other mechanical properties to predict the plane strain fracture toughness of materials, their methods have certain limitations in terms of testing methods and theoretical applicability. limitations

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