动态应变时效对奥氏体不锈钢纯弯疲劳强度的影响

EFFECTS OF DYNAMIC STRAIN AGING ON PURE BENDING FATIGUE STRENGTH OF AUSTENITIC STAINLESS STEEL

本文着重研究了动态应变时效(DSA)预处理对18-8型奥氏体不锈钢室温纯弯疲劳强度的影响。结果表明,DSA预处理显著提高材料纯弯疲劳强度,其强化效果随预应变温度和预应变量的增加而提高,其疲劳极限比固溶态提高87%,比相应的冷变形态提高20%。金属薄膜电镜观察结果表明,材料经DSA预处理后,形成了均匀、高密度、稳定的位错网络结构。在随后的疲劳过程中,它们有效地抑制了疲劳裂纹的萌生和扩展。

DSA pre-treatment processes increase remarkably the fatigue strengthand the strenthening effects increase with increasing prestrain temperature and pre-strain. TBM observation shows that the uniform and stable dislocation networkswith high density form after DSA pre-treatment, which suppress effectively the in-ititation and propagation of fatigue crack and increase the fatigue strength.