高强耐蚀Ni-Co-Cr高温合金的组织稳定性

STRUCTURE STABILITY OF HIGH STRENGTH ANDCORROSION RESISTING Ni-Co-Cr SUPERALLOY

利用SEM,TEM及X射线衍射分析技术观察了高强耐蚀Ni-Co-Cr高温合金不同温度(704,750,849℃)长期时效1000 h及700℃长期时效至5008 h过程中的组织演变过程,结果表明,700℃即使长期时效5008 h,γ'相粗化缓慢, 而且没有发现TCP相(如σ相)的析出,当温度升高到750℃,γ'相迅速长大,晶界上碳化物析出增多,并析出片状的η相,导致合金冲击性能下降,温度达到849℃时,析出大量的η相,甚至形成魏氏组织形貌,由此可见,该合金在700℃时具有较好的组织稳定性。

The structure stability of a new high temperature corrosion-resistance superalloy was investigated at different temperatures (704. 750. 849 C ) for 1000 h long-term aging and 700 up to 5008 h using SEM. TEM and X-ray diffraction analyses. The experimental results show that r' phase remains relative stability, and TCP phase, such as phase, has not been detected. However, with increasing the aging temperature to 750 . the coarsening rate of r' phase increased rapidly, n phases appeared, and an M23C6 carbides precipitation increased at some grain-boundaries. For 849 aging to 1000 h. numerous n phases were observed. Therefore, the tested alloy has a good structure stability at 700.