Effect of Skew Angle of Holes on the Thermal Fatigue Behavior of a Ni-based Single Crystal Superalloy  

作　　者：Zhong-Jiao Zhou Da-Qian Yu Li Wang Lang-Hong Lou 

机构地区：[1]Superalloys Division, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China [2]Division of Micro/Nano Manufacturing, State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China [3]Material Design and Research Section, Beijing Huatsing Gas Turbine & IGCC Technology Co., Ltd., Tsinghua Science Park, Beijing 100084, China

出　　处：《Acta Metallurgica Sinica(English Letters)》2017年第2期185-192,共8页金属学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(No.51201164);the National High Technology Research and Development Program of China(No.2012AA03A511)

摘　　要：In the present work,holes of various skew angles were electrochemically machined in the middle of the plate specimens in a Ni-based single crystal superalloy and crack initiation and propagation around holes during thermal fatigue cycles（20–1100 ℃） were investigated.It was demonstrated that the skew angles had a significant effect on the initiation and propagation of thermal fatigue cracks.During thermal fatigue process,stress concentration occurred at the edge of the holes.As for skew angles,the maximum stress concentration appeared at the acute side of holes.The maximum stress concentration resulted in plastic deformation at the acute side of the 30° hole,driving the thermal fatigue cracks to initiate after 220 cycles and propagate along [011] direction.However,the stresses concentrated at the edge of 90° or 60° holes were not large enough to initiate cracks even after 580 thermal cycles.This work will help to understand the local deformation behavior in the vicinity of cooling holes with various skew angles and have serious design implications for turbine blades.In the present work,holes of various skew angles were electrochemically machined in the middle of the plate specimens in a Ni-based single crystal superalloy and crack initiation and propagation around holes during thermal fatigue cycles（20–1100 ℃） were investigated.It was demonstrated that the skew angles had a significant effect on the initiation and propagation of thermal fatigue cracks.During thermal fatigue process,stress concentration occurred at the edge of the holes.As for skew angles,the maximum stress concentration appeared at the acute side of holes.The maximum stress concentration resulted in plastic deformation at the acute side of the 30° hole,driving the thermal fatigue cracks to initiate after 220 cycles and propagate along [011] direction.However,the stresses concentrated at the edge of 90° or 60° holes were not large enough to initiate cracks even after 580 thermal cycles.This work will help to understand the local deformation behavior in the vicinity of cooling holes with various skew angles and have serious design implications for turbine blades.

关 键 词：Ni-based single crystal superalloy Thermal fatigue properties HOLES Skew angles Cracks 

分 类 号：TG132.3[一般工业技术—材料科学与工程]