• CN: 11-2187/TH
  • ISSN: 0577-6686

Journal of Mechanical Engineering ›› 2020, Vol. 56 ›› Issue (21): 208-218.doi: 10.3901/JME.2020.21.208

Previous Articles     Next Articles

Influence of Heat Treatment on Microstructure Evolution of GH3536 Superalloy Fabricated by Selective Laser Melting

SUN Shanshan1, TENG Qing1, CHENG Tan1, WANG Jiwei2, CHEN Jixiang2, BAI Jie3, LIU Zhifu3, WEI Qingsong1   

  1. 1. State Key Laboratory of Material Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan 430074;
    2. Shenzhen Institute & Information Technology, Shenzhen 518172;
    3. Beijing Power Machinery Institute, Beijing 100071
  • Received:2019-11-23 Revised:2020-06-15 Online:2020-11-05 Published:2020-12-19

Abstract: GH3536 superalloy is fabricated by selective laser melting (SLM), its microstructure evolution and crack variation under various heat treatments are studied. Microstructure evolution and phase identification are conducted by XRD, SEM, EPMA, EBSD, and TEM. the results indicate that the main constituent phase of specimens fabricated by SLM is γ phase. Needle-rod and lamellar phases which are rich in C、Cr and Mo elements are formed inside the grains, as well as the grain boundaries after heat treatment, These phases are mainly composed of Laves phase and carbides. The melt pool boundaries of specimens fabricated by SLM gradually become shallow and disappear after heat treatment, because of the improved diffusion effect of alloying elements. The average grain size of specimens fabricated by SLM is 13.18 μm, and it decreases to 12.01 μm after solution treatment, and the grain size is obviously refined to 10.87 μm after hot isostatic pressing, as a result of recrystallization. Micro-cracks can be observed in the matrix after SLM process, and the length is measured ranging from 10 to 100 μm. These cracks are found to originate inside the melt pool, and penetrate through the melt pool. After direct aging heat treatment and solution heat treatment, the size and distribution of micro-cracks do not improve significantly. However, after hot isostatic pressing, the micro-cracks are almost eliminated.

Key words: selective laser melting, GH3536 superalloy, heat treatment, HIP, microstructure

CLC Number: