| Title |
Effect of Hf on Microstructures and High Temperature Low Cycle Fatigue characteristics of DS Rene 80 Alloy |
| Authors |
현용택(Yong Taek Hyun); 황선근(Sun Keun Hwang); 최재호(Jae Ho Choi); 김학민(Hak Min Kim); 조종춘(Jong Chun Cho) |
| Abstract |
The effects of Hf on microstructures and high temperature low cycle fatigue(LCF) behavior of directionally solidified Rene 80 (DS Rene 80) alloy were studied. LCF tests were conducted at 760℃, 871℃ and 982℃, respectively. The fatigue properties of Elf -modified DS Rene 80H alloy were superior to those of DS Rene 80 alloy under all experimental conditions. The beneficial effect of Elf was found to be twofold : it increased the resistance to crack propagation by changing the morphology of carbides from script-type to blocky-type, and suppressed the crack initiation by increasing the resistance to oxidation. Cyclic softening was observed during high temperature LCF tests. At 760℃, the mechanism for the cyclic softening was disordering of γ` preciptates due to dislocation shearing; at 982℃, it appeared to be mainly the loss of coherency between matrix and T`s and partly the coarsening of γ`s. |