摘要
用金相显微镜、扫描电镜(SEM)及带有切口的三点弯曲试样研究了显微组织对珠光体钢疲劳裂纹扩展速率的影响。结果表明:共析珠光体钢中的疲劳裂纹扩展速率da/dN取决于珠光体层片间距。细化珠光体层片间距可有效减缓共析珠光体钢中的疲劳裂纹扩展速率,尤其在高应力场强度因子幅值△K作用的情况下;珠光体钢的疲劳裂纹扩展速率与断裂前的△K之间的关系为:da/dN=6.94×10^(-9)(△K)^(2.919) (mm·c^(-1));显微组织中存在一定量的先共析铁素体可显著降低珠光体钢中疲劳裂纹的扩展速率。
The effect of microstructure on propagation rate of fatigue crack was investigated by SEM and three point bending specimens with notch. The results show that the propagation rate of fatigue crack in eutectoid pearlitic steels (da/dN) is dependent on the interlamellar spacings of pearlite. The da/dN can be effectively decreased through refining the interlamel-lar spacings in steels, especially when the stress field intensity factor (ΔK is high. The following quantitative relationship between the da/dN and ΔK before fracture exist: da/dN = 6.94×10-9 (Δ/K )2.919 (mm·c-1). The presence of some proeutectoid ferrite can delay obviously the propagation of the fatigue crack in pearlitic steels also.
出处
《物理测试》
CAS
2004年第2期7-10,共4页
Physics Examination and Testing
