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弹性变形会引起杂质元素在晶界处浓度的改变,这将导致晶界脆性的发生。基于多晶金属弹性变形的微观理论,研究了拉伸试验弹性变形过程中金属材料的脆性,探讨了应变速率对材料力学性能的影响,提出了临界应变速率和应变速率脆性的概念。应变速率脆性是一种应变速率改变引起的晶界脆性,在临界应变速率下,应变速率脆性达到极大值。随着测试温度的降低,临界应变速率向低应变速率移动,这是应变速率脆性的一个基本特征。临界应变速率的存在及应变速率脆性的特征已从大量文献的试验结果得到证实。
Elastic deformation will cause the concentration of impurity elements in the grain boundary changes, which will lead to the occurrence of grain boundary brittleness. Based on the microscopic theory of elastic deformation of polycrystalline metal, the brittleness of metal material during the elastic deformation of tensile test was studied. The effect of strain rate on the mechanical properties of the material was also discussed. The concepts of critical strain rate and brittleness of strain rate were also proposed. Strain rate Brittleness is a grain boundary brittleness caused by a change in strain rate, at which the strain rate brittleness reaches a maximum value. As the test temperature decreases, the critical strain rate moves to a low strain rate, which is an essential feature of strain rate brittleness. The existence of critical strain rate and the brittleness of strain rate have been confirmed by a large number of literature test results.