Exploring the evolution of microstructure and mechanical property of aγʹ-strengthened Co-based single crystal superalloy during creep and thermal exposure at 1000℃  

作　　者：Zhen Xu Chuan Guo Yu Li Zhiwei Lv Xiaogang Hu Xinggang Li Qiang Zhu 

机构地区：[1]Department of Mechanical and Energy Engineering,Southern University of Science and Technology,Shenzhen 518055,China [2]Shenzhen Key Laboratory for Additive Manufacturing of High-performance Materials,Shenzhen 518055,China [3]CityU-Shenzhen Futian Research Institute,Shenzhen 518045,China

出　　处：《Journal of Materials Science & Technology》2024年第36期39-52,共14页材料科学技术(英文版)

基　　金：supported by the China Post-doctoral Science Foundation(No.2023M731500);the Shen-zhen Science and Technology Innovation Commission,China(Nos.JCYJ20210324104610029,KQTD20170328154443162,and JCYJ20220818100613028);the National Natural Science Foundation of China(No.52250710160),the National Key Research and De-velopment Program of China(No.2017YFB0702901);the Shenzhen Key Laboratory for Additive Manufacturing of High-performance Materials(No.ZDSYS201703031748354)。

摘　　要：The study provided a systematic investigation into the creep behavior of aγʹ-strengthened Co-based single crystal superalloy Co-7Al-8W-1Ta-4Ti(at.%)under compressive creep conditions at 1000℃and 137 MPa.Simultaneously,the microstructural changes during thermal exposure at 1000℃ were thor-oughly examined.The microstructure analysis of the creep samples revealed the presence ofγ/γʹrafts,twins,stacking faults,and dislocation networks.Statistical analyses were conducted to assess the dimen-sions and volume fractions ofγʹ,alongside Vickers hardness tests and nanoindentation experiments.Re-sults show thatγʹdissolution in the creep samples with substantially higher dissolution rates compared to thermal exposure.Localized Co depletion and Ti enrichment in twin is observed in creep sample,po-tentially initiating localized phase transformations.Concurrently,lattice rotation occurred during creep,resulting in a progressive deviation of crystal orientation away from the[001]direction.Stacking faults transitioned from network-like structures to parallel configurations,and twins played a significant role in creep deformation,particularly in samples subjected to 382 h creep.The study also explored the evo-lution of Vickers hardness and the elastic modulus,introducing a systematic linear model to describe Vickers hardness changes during both thermal exposure and creep conditions.

关 键 词：SUPERALLOY ompressive creep Thermal exposure Vickers hardness TWINNING 

分 类 号：TG1[金属学及工艺—金属学]