晶粒尺寸对高锰奥氏体TWIP钢氢脆行为的影响

主要研究了晶粒尺寸对Fe- 17Mn- 1Al- 0.6C TWIP钢的氢脆行为的影响。原始材料经过不同的热处理制度，得到晶粒尺寸为17和45μm的材料。通过慢拉伸试验研究氢质量分数在0～0.001%材料的氢脆敏感性。试验结果表明，充氢后的试验材料比未充氢试验材料易发生氢脆，充氢后的试验材料断裂强度和断裂应变均降低。随着晶粒尺寸的增大，试验材料的氢脆敏感性增强。在氢质量分数为0.001%，晶粒尺寸增加到45μm时，应变损失率为17%，随着晶粒尺寸的增大，氢脆敏感性增加的原因是晶粒尺寸较大的材料孪晶较早出现，孪晶密度较大，同时单位晶界氢质量分数增加。

Effect of grain size on hydrogen embrittlement of high Mn austenitic TWIP steel

The effects of grain size on hydrogen embrittlement of Fe- 17Mn- 1Al- 0.6C TWIP steel was investigated. The as- delivered material was annealed at different annealing cycles and the grain sizes of the material obtained was 17μm and 45μm, respectively. The susceptibility to hydrogen embrittlement was investigated by carrying out slow strain rate test with hydrogen pre- charged specimens in condition of the hydrogen in the range of 0- 0.001%. Results showed that it was easier for hydrogen embrittlement to occur in the hydrogen pre- charged specimens more than in the uncharged ones. As the same time, both fracture strength and strain in the hydrogen pre- charged specimens declined in comparison to the uncharged condition. Besides, the materials obtained higher susceptibility to hydrogen embrittlement as grain size increased. By raising the grain size from 17μm to 45μm, the strain loss was raised 17% with the pre- charged hydrogen in 0.001% level. The increase of the susceptibility to hydrogen embrittlement in the material with grain sizes increased can be explained by the early initiation of the twins in the material with coarser grain sizes and high density of deformation twins as well as the raised hydrogen content per unit grain boundary area.