Effect of Hf on Stress Rupture Properties of DD6 Single Crystal Superalloy After Long Term Aging

作     者：SHI Zhen-xue LI Jia-rong LIU Shi-zhong 

作者机构：National Key Laboratory of Science and Technology on Advanced High Temperature Structural MaterialsBeijing Institute of Aeronautical Materials Beijing 100095China 

出 版 物：《Journal of Iron and Steel Research(International)》 (钢铁研究学报（英文版）)

年 卷 期：2012年第19卷第7期

页      面：66-70页

核心收录：

学科分类：08[工学] 0806[工学-冶金工程] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 0703[理学-化学] 0801[工学-力学（可授工学、理学学位）] 0702[理学-物理学] 

主　　题：DD6 single crystal superalloy stress rupture property long term aging 

摘      要：The specimens of the second generation single crystal superalloy DD6 with different Hf contents were prepared in the directionally solidified furnace with a high temperature gradient. The long term aging of the specimens after full heat treatment was performed at 1040℃for 800 h. The effect of Hf on the microstructure and stress rupture properties under 980℃/250 MPa of the alloy after long term aging was investigated. The results show that the γ＇ coarsening and rafting and no topologically close packed phase （TCP） are observed in the microstructures of DD6 alloy with different Hf contents after aged at 1 040℃ for 800 h. It indicates that DD6 alloy with different Hf contents all possesses good microstructure stability. With increasing Hf content the rupture life after long term aging turns shorter and the elongation represents the increasing first and decreasing afterwards. The fracture mechanism of the alloy with different Hf contents at 980℃/250 MPa all shows dimple model. The influence of the microstructures on the stress rupture properties of the alloy is also discussed.