定向凝固合金叶片的再结晶与疲劳失效

 对定向凝固合金叶片的裂纹与断裂进行了分析,在断口观察与金相组织分析的基础上,对叶片的失效模式与失效原因进行了研究,并提出了预防该类故障发生的措施。研究结果表明,定向凝固合金叶片的裂纹与断裂为同一失效模式,均为叶片表面的再结晶而导致的疲劳失效。叶片表面的再结晶在叶片使用之前就已存在,是由于固溶热处理前叶片的表面存在塑性变形,在固溶热处理过程中形成的。

Recrystallization and Fatigue Failure of Blades Made of a Directionally Solidified Alloy

The crack and fracture of blades made of a directionally solidified superalloy were analyzed. The failure mode and cause were studied in virtue of fracture observation and metallographic structure analysis. The results show that the crack and fracture on the superalloy blades have the same failure mode resulting from surface recrystallization. Owing to the plastic deformation at the blade surface, recrystallization formed during the solid solution heat treatment. Before blade application, the recrystallization zone is already exist on its two sides and surface.