Method for evaluating microcrack initiation of magnesium alloy

Abstract

The invention discloses a method for evaluating microcrack initiation of magnesium alloy. The method includes the following steps that an in-situ tension method is adopted for acquiring the data of an in-situ scanning electron microscope (SEM) and the data of in-situ electron back scattering diffraction (EBSD); according to the data of the in-situ SEM and the data of the in-situ EBSD, the eulerian angles representing grain orientation information are acquired; in accordance with the eulerian angles, the crack initiation parameter F1 is calculated, and the possible microcrack initiation position is predicted. According to the method for evaluating the microcrack initiation of the magnesium alloy, the in-situ EBSD method is adopted so that slipping and twinning information in grains and microcrack initiation in the uniaxial drawing process of the magnesium alloy can be observed dynamically; the correlation between microcrack initiation on the grain boundary and the orientation and stress direction of surrounding grains can be evaluated comprehensively through calculation of the crack initiation parameter F1; the nucleation and the happening position of microcracks can be accurately predicted through calculation of the F1 value, and it is of great significance to improve the plasticity of the magnesium alloy.

Description

Technical field [0001] The invention relates to the technical field of testing, in particular to a method for evaluating the initiation of microcracks in magnesium alloys. Background technique [0002] At present, among various failures of metal materials, fracture failure is the most important and the most harmful. The crack is the prelude to fracture failure. Therefore, predicting the initiation position of microcracks is of great significance for fracture failure caused by cracks. [0003] There are two different methods for existing research on fracture behavior. One is the method of fracture mechanics, which is based on the elasticity and elastoplastic theory of metals, and considers the existence of defects in the material to establish a method of studying fracture behavior. The other is the method of metal physics, which studies the fracture behavior from the microstructure of the material, the micro defect, and even the molecular and atomic scale. The research methods o...

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Problems solved by technology

[0004] At present, for the generation of microcracks in magnesium alloy materials and the failures caused by them, the existing research methods include using ion beam grid (FIB) for the deformation area, and analyzing the effect of local strain on microcracks by drawing strain nephograms for the degree of grid deformation. However, this method focuses on the influence of the local strain at the grain boundary on microcracks, and does not consider the influence of grain orientation, twinning and slip around the grain boundary

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