Experimental Investigation on the LCF Behavior Affected by Manufacturing Defects and Creep Damage of One Selective Laser Melting Nickel-Based Superalloy at 815℃  

作　　者：Xiao-An Hu Gao-Le Zhao Yun Jiang Xian-Feng Ma Fen-Cheng Liu Jia Huang Cheng-Li Dong 

机构地区：[1]School of Aircraft Engineering,Nanchang Hangkong University,Nanchang 330063,China [2]Jiangxi Key Laboratory of Micro Aeroengine Technology,Nanchang 330063,China [3]Sino-French Institute of Nuclear Engineering and Technology,Sun Yat-Sen University,Zhuhai 519082,China [4]National Defence Key Discipline Laboratory of Light Alloy Processing Science and Technology,Nanchang 330063,China [5]School of Aeronautics and Astronautics,Central South University,Changsha 410083,China [6]Materials Evaluation Center for Aeronautical and Aeroengine Application,AECC Beijing Institute of Aeronautical Materials,Beijing 100095,China

出　　处：《Acta Metallurgica Sinica(English Letters)》2020年第4期514-527,共14页金属学报（英文版）

基　　金：This research was financially supported by the National Natural Science Foundation of China(No.U 1633113);the National Natural Science Foundation of China(No.NSFC51905249);the Natural Science Foundation of Jiangxi Province(No.20192BAB216020).

摘　　要：Uniaxial tensile tests and stress-controlled low-cycle fatigue(LCF) and creep-fatigue interaction(CFI) tests of Inconel 625 alloy manufactured by selective laser melting(SLM) were performed at 815℃ in air environments.The microstructure was characterized by optical microscopy and scanning electron microscopy after testing.The results confirmed that significant embrittlement and large scatter in LCF life are resulted from manufacturing defects.The CFI life is decreased sharply to approximately dozens of cycles with the accumulated creep strain;however,the selected dwell time(i.e.,60 s and 300 s)exhibits low sensitivity to the fracture time and elongation to failure.The embrittlement of SLM Inconel 625 was proposed to be due to the low grain uniformity and precipitation of carbides at the grain boundaries.Due to the quality of the SLM process,the accelerated initiation and propagation of fatigue crack are caused by the present unmelted powder particles,which result in the large dispersion of LCF life.Meanwhile,due to the accumulation of creep damage,cracks in the CFI test are initiated along the grain boundaries and then linked together,contributing to a significant decline in fatigue life.

关 键 词：Selective laser MELTING Low-cycle fatigue CREEP-FATIGUE interaction Failure analysis 

分 类 号：TG132.3[一般工业技术—材料科学与工程]