The role of δ phase for fatigue crack propagation behavior in a Ni base superalloy at room temperature

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• 作者：Jinlan An ; Lei Wang ; ^{wanglei@mail.neu.edu.cn} ; Yang Liu ; Wenliang Cai ; Xiu Song
• 关键词：δ phase ; Fatigue crack propagation behavior ; Ni base superalloy ; Microstructure characteristics
• 刊名：Materials Science and Engineering: A
• 出版年：2017
• 出版时间：27 January 2017
• 年：2017
• 卷：684
• 期：Complete
• 页码：312-317
• 全文大小：3262 K
• 卷排序：684

文摘

The fatigue crack propagation behavior of a Ni base superalloy at room temperature with various volume fractions of δ phase was investigated. The result shows that fatigue crack growth rate of the alloy increases as δ phase volume fraction increases, while both the fatigue crack propagation resistance and the strength of the alloy decrease. The characteristic of δ phase on crack propagation behavior is depended on the dislocations slipping blocked by granular δ phase with low length-diameter radio. On the other hand, dislocations easily piled up around long needle-like δ phase which leads to stress concentration. This stress concentration causes δ phase debonding from the matrix and helps the crack easy propagates along long needle-like δ phase surrounded by precipitates free zone (PFZ).