Analysis of theelectric and thermal effects on mechanical behavior of SS304 subjected toelectrically-assisted forming process
Analysis of theelectric and thermal effects on mechanical behavior of SS304 subjected toelectrically-assisted forming process
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电辅助成形过程中电热效应对SS304力学行为的影响分析
DOI：
10.1115/1.4032118
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通讯作者：
来新民
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作者：
姜天豪;彭林法;易培云;来新民
在电辅助成形（EAF）过程中观察到金属的变形抗力和延展性的显著改善。提出了电流引起的电塑性效应和焦耳加热引起的热效应来解释这一现象。然而，对于EPE在EAF过程中的贡献，仍然存在争议。本文对SS304试样在相同温度下进行了电辅助拉伸试验（EAT）和热辅助拉伸试验（TAT）。研究了EPE的存在性，并从初始屈服应力、位错硬化和马氏体相变三个方面对EPE的贡献与热效应进行了数值区分。结果表明，当温度在34℃左右时，与TAT相比，50 A/mm2in EAT电流诱导的与初始屈服应力相关的短时内应力（有效应力）的额外应力减小了16%，马氏体形成的体积减小了45.2%。当温度高于100℃时，在100a /mm2和150a /mm2情况下，效果不明显。通过比较位错在EAT和TAT中的储存系数和恢复系数，表明电流对SS304的位错运动没有额外的激活作用。
Significant improvements in deformation resistance and ductility of metals are observed in the electrically assisted forming (EAF) process. Both electroplastic effect (EPE) induced by electric current and thermal effect associated with Joule heating have been proposed to explain the phenomenon. However, there are still arguments in the contribution of the EPE in EAF process. In this paper, both electrically assisted tension tests (EAT) and thermally assisted tension tests (TAT) were conducted on SS304 specimens at the same temperature. The existence of EPE is investigated, and the contribution of EPE is also distinguished with thermal effect numerically by considering the initial yield stress, dislocation hardening, and martensite phase transformation. It is shown when the temperature is around 34 °C, the electric current of 50 A/mm2in EAT induces additional stress reduction of 16% in the short-range internal stress (effective stress) involved in the initial yield stress and volume reduction of 45.2% in martensite formation compared with results in TAT. However, the effect is not obvious for the cases of 100 A/mm2and 150 A/mm2when the temperature is above 100 °C. By comparing the storage coefficient and recovery coefficient of dislocation in EAT and TAT, it indicates that electric current has no additional activation effect on dislocation movement of SS304.