Abstract A quasi-static tensile test was performed on a 1.4 mm-thick TRIP780 steel strip with welding points. An MTS810 material test machine was used in the test, and a Split Hopkinson tension bar device was used in performing impact stretch loading at different strain rates. The dynamic tensile stress–strain curve of the spot welding material with different strain rates was obtained through the finely designed Hopkinson rod test, and the strain rate dependence of a TRIP780 steel spot welding material was discussed. According to the dynamic constitutive equation of the TRIP780 steel spot welding material, the test results were numerically simulated, the constitutive description and test curves were compared, and the simulation results and test results were discussed and analyzed. The fractures of the test recovery specimen were scanned with the scanning electron microscope, and the fracture mechanism of the TRIP780 steel spot welding material was explored by observing the fractures. The surfaces of the fractures surface showed obvious cleavage river patterns, and the evolution process of microcracks was determined and used in characterizing brittle fractures in specimen spot welding sample subjected to dynamic stretch loading.

中文翻译：

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TRIP780钢电阻点焊材料的霍普金森棒试验结果和本构描述

摘要 对1.4 mm厚的带焊点的TRIP780钢带进行了准静态拉伸试验。试验采用MTS810材料试验机，采用Split Hopkinson拉杆装置进行不同应变率下的冲击拉伸加载。通过精细设计的霍普金森棒试验获得了不同应变率点焊材料的动态拉伸应力-应变曲线，并讨论了TRIP780钢点焊材料的应变率依赖性。根据TRIP780钢点焊材料的动态本构方程，对试验结果进行数值模拟，对比本构描述和试验曲线，并对模拟结果和试验结果进行了讨论和分析。用扫描电镜对试验恢复试样的断口进行扫描，通过观察断口来探索TRIP780钢点焊材料的断口机理。断裂面表面呈现明显的解理河纹，确定了微裂纹的演化过程，并用于表征动态拉伸载荷下试样点焊试样的脆性断裂。