【摘要】 研究了 30 0 M超高强度钢油淬和 2 70℃等温淬火组织中残余奥氏体 (AR)对冲击疲劳性能的影响 .结果表明 ,残余奥氏体量越多 ,冲击疲劳裂纹起始寿命 Ni 越低 ,裂纹扩展速率 da/ d N越快 .AR作为软相 ,使板条间易于相对滑移 ,产生微裂纹 .AR对 da/ d N影响的主要机制是裂纹尖端塑性区内的应变诱发马氏体相变 .更多还原

【Abstract】 By varying the amount of retained Austenite (A R) in oil quenching and isothermal quenching at 270℃ the impact fatigue behavior of 300 M ultrahigh strength steel was investigated.The results show that with the increase of the retained Austenite amount,the impact fatigue crack initiation life N i decreases,the crack propagation rate da/dN speeds up.As in soft phase,A R makes martensite or bainite laths easy to slide,and leads to micro crack initiation.The main mechanism of the influence of A R on da/dN is the localized TRIP.更多还原