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金属高温拉伸试验国际技术标准ISO 6892-2-2011认定,拉伸试验的拉伸温度或应变速率的改变会引起拉伸试验测试力学性能结果的不确定性,危及到拉伸试验技术的可靠性.本文综述了拉伸试验测试断面收缩率或延伸率的不确定性:中温脆性和应变速率脆性的实验现象和特征,简述了多晶金属弹性变形微观理论的基本结果,以此微观理论解释了上述两种测试不确定性的试验现象,阐明了这两种测试不确定性是拉伸试验弹性变形阶段杂质晶界偏聚,脆化了晶界引起的.为修正金属拉伸试验技术标准,避免断面收缩率测试的不确定性提供了理论基础.
The International Technical Standard for High Temperature Tensile Testing of Metals, ISO 6892-2-2011, identifies that the change in the stretching temperature or strain rate in a tensile test can lead to uncertainties in the tensile test results and compromise the reliability of the tensile test technique In this paper, the experimental results and characteristics of the brittleness at medium temperature brittleness and strain rate, the basic results of microscopic theory of elastic deformation of polycrystalline metal are briefly introduced. Based on the microscopic theory The test results of the above two kinds of test uncertainty are explained, and the uncertainty of these two tests is explained by the segregation of grain boundaries and the embrittlement of grain boundary in the elastic deformation stage of tensile test.In order to modify the metal tensile test technique Standard, to avoid the cross-sectional shrinkage test uncertainty provides a theoretical basis.