针对ISO 10275: 2007及GB/T 5028-2008中对于材料在拉伸时呈现锯齿屈服效应曲线如何计算拉伸应变硬化指数n值的问题, 就未呈现锯齿屈服效应的曲线和呈现锯齿屈服效应的曲线, 采用国际线性回归法计算nline, 并用Zwick试验机采用回归法测试ntest以及用差分平均法测试nsingle, 同时对三种测试方法进行比较。结果表明: 对于不呈现锯齿屈服效应的曲线, 可以同时采用上述三种方法; 而对于呈现锯齿屈服效应的曲线, 不能采用差分平均法测试nsingle, 只能采用国际线性回归法计算nline以及采用Zwick试验机用回归法测试ntest。且对于呈现锯齿屈服效应的曲线测试nline和ntest, 回归区间不宜太小。

Based on how to calculate tensile strain hardening exponent n value with a serrated yield effect curve prescribed in ISO 10275:2007 and GB/T 5028-2008,three test methods were used including the international linear regression test for nline, the linear regression test for ntest and the difference average test for nsingle with Zwick testing machine, and a comparison of three test methods was maken to with a serrated yield effect curve and without a serrated yield effect curve. The results showed that the international linear regression test for nline, the linear regression test for ntest and the difference average test for nsingle with Zwick testing machine can be used at the same time to without a serrated yield effect curve. While to with a serrated yield effect curve, the difference average test for nsingle can not be used, the methods to test nlineand ntest can be used. Meanwhile nline and ntest were tested with a serrated yield effect curve, the regression interval should not be too small.