Abstract Stress relaxation tests were carried out to identify stress relaxation limit of Inconel718 under different testing conditions. Experimental results indicated that stress relaxation limits calculated by function-fitting were consistent with testing data at service temperatures and low initial stress because of the rapid reaching of steady state. However, there exist large deviations using the same method under testing conditions of over-temperatures or high initial stress (near yield stress). Reasons for these are related to stress relaxation mechanism which can be illustrated by microstructure evolution: diffusion motion accelerates remarkably at high temperature, while multiple forms of plastic deformation occurs at high initial stress.

中文翻译：

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Inconel718高温合金函数拟合计算应力松弛极限的局限性

摘要 为了确定Inconel718在不同测试条件下的应力松弛极限，进行了应力松弛试验。实验结果表明，由于快速达到稳态，函数拟合计算的应力松弛极限与使用温度和低初始应力下的测试数据一致。然而，在超温或高初始应力（接近屈服应力）的测试条件下，使用相同的方法存在较大偏差。其原因与应力松弛机制有关，可以通过微观结构演化来说明：扩散运动在高温下显着加速，而在高初始应力下发生多种形式的塑性变形。