碳化钨钢结硬质合金热疲劳裂纹形成机理研究

对含有35%WC 的钢结硬质合金在热应力作用下热疲劳裂纹形成过程进行了反复观察。结果表明:此过程存在明显的裂纹萌生孕育期:首先在缺口边缘上出现凹坑;随着热循环次数的增加, 凹坑数目增多且尺寸变大。第一条热裂纹在最早出现的凹坑底部形成。与此同时, 在缺口前沿区, 原有的及后生的微孔也随热循环次数的增加而增多且变大;最终, 微孔连接形成热裂纹。

The Forming Mechanism of Thermal Fatigue Crack of Steel Bonded Carbide

Thermal fatigue crack forming process of steel bonded carbide containing 35% WC by the action of thermal stress has been observed time and time again. The results show that there was an obvious incubation period of crack forming, at first some pits appeared on the verge of the sample notch; the number and size of these pits increased with the increase of the cycle number. The first crack formed on the bottom of the pit for the first time. At the same time, the number and size of microscope holes in front of the sample notch increased with the increase of the thermal cycling number, and finally microscopic holes formed crack by their connection with each other.