低Re含量第二代柱晶高温合金DZ59的蠕变断裂性能

采用液态金属冷却(LMC)工艺和成分优化设计,制备出一种高温性能优异的低Re含量第二代柱晶高温合金DZ59,通过扫描电镜(SEM),透射电镜(TEM)等方法对其组织特征及蠕变断裂进行了表征,研究了合金的蠕变断裂性能.结果表明,DZ59合金的高温蠕变断裂性能超过一代单晶合金,并接近二代单晶合金的水平.发现柱晶高温合金的二次晶界反应(SGRZ)现象,表明SGRZ受温度和应力的控制,由于增加了合金横向晶界的受力界面,在高负荷下可能成为蠕变空洞萌生和扩展的位置.

The creep rupture properties of a low Re content second-generation directionally solidified superalloy DZ59

Assisted by the advanced LMC process and an optimum composition design, a highperformance second-generation directionally solidified superalloy DZ59 with low Re content has been developed. The high temperature creep properties of the superalloy are better than first-generation single crystal alloys and is close to the level of second-generation single crystal alloys. The microstructure and creep rupture feature of the DZ59 alloy have been analysed in detail by SEM and TEM. The SGRZ was first discovered in the second-generation directionally solidified superalloys. The results showed that SGRZ is controlled by the temperature and stress. Because SGRZ increases the area of transverse grain boundary, creep voids may initiate and propagate in the SGRZ location under high stress.