一种镍基单晶高温合金中碳化物热稳定性研究

Thermal stability of carbides in a Ni-based single crystal superalloys

利用SEM、TEM研究了一种镍基单晶高温合金中碳化物在950℃时效不同时间的退化规律。固溶处理过程中形成的MC碳化物随时效时间的增加而逐渐退化为M6C和M23C6碳化物。同时,由于在时效处理过程中Re元素进入M6C碳化物中,破坏了其结构稳定性,促使M6C碳化物也可以退化为M23C6碳化物。至时效3 000 h时,没有观察到碳化物退化的逆反应。本研究可以为高温合金高温下服役的稳定性提供实验参考。

The degradation of carbides in a nickel-based single crystal superalloys exposed at 950 ℃ for different times were investigated by scanning electron microscopy and transmission electron microscopy. The MC carbide formed during the solution treatment gradually degenerates to M6C and M23C6 carbides with the increase of exposure time. Degradation of the M6C carbides to M23C6 is due to the entering of Re into the M6C carbides during aging treatment,which breaks the structure stability of M6C. There is no reverse reaction of the degradation,even after 3000 h exposure. This study provides experimental insight into the structure stability of superalloys serve at high temperature.