Acta Metallurgica Sinica (English Letters) ›› 2022, Vol. 35 ›› Issue (9): 1477-1493.DOI: 10.1007/s40195-022-01421-7

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Microstructure and Mechanical Properties of Graphene Reinforced K418 Superalloy by Selective Laser Melting

Yongxin Lu1,2,3,6(), Fan Luo1, Zhen Chen4, Jian Cao2, Kai Song5, Lei Zhao5, Xueli Xu1,6, Hongduo Wang1,6, Wenya Li3   

  1. 1School of Material Science and Engineering, Xi’an Shiyou University, Xi’an, 710065, China
    2State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin, 150001, China
    3School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an, 710072, China
    4State Key Laboratory of Manufacturing System Engineering, Xi’an Jiaotong University, Xi’an, 710049, China
    5School of Materials Science and Engineering, Tianjin University, Tianjin, 300350, China
    6Xi’an Key Laboratory of High Performance Oil and Gas Field Materials, Xi’an Shiyou University, Xi’an, 710065, China
  • Received:2022-02-07 Revised:2022-03-20 Accepted:2022-04-03 Online:2022-09-10 Published:2022-06-09
  • Contact: Yongxin Lu
  • About author:Yongxin Lu, luyongxin618@163.com

Abstract:

In order to obtain the superalloy with excellent properties, graphene reinforced K418 nickel base superalloy (GNPs/K418 composite) was prepared by selective laser melting technique in this study. Through systematically comparing and analyzing the microstructure and mechanical property of K418 superalloy and GNPs/K418 composite, it is found that the percentage of small-diameter grain (≤ 15 μm) increased from 84% to 90%, and the max strength of grain orientation (<001>) reduce from 5.76 to 4.17 due to the addition of GNPs. And GNPs can also improve the height and the full width at the half peak of the strong diffraction peak of GNPs/K418 composite. Besides, GNPs/K418 composite is a kind of sandwiched structure, which is consist of GNPs, carbides, and K418 matrix. Therefore, the hardness of the GNPs/K418 composite is 4.1% and 6.9% higher than that of the K418 matrix in the transverse and vertical direction, respectively. The room temperature tensile strength of the GNPs/K418 composite is 9% higher than that of the K418 matrix. And the 600 °C and 900 °C tensile strengths of the GNPs/K418 composite are 7.6% and 10.4% higher than that of the K418 matrix, respectively. It is inferred that the effect of graphene on K418 matrix strengthening is mainly fine grain strengthening and Orowan strengthening. However, the elongation rate of the composite material is reduced, which is attributed to crack sprouting at the interface between the matrix and GNPs under high stress.

Key words: Graphene, K418 nickel base superalloy, Selective laser melting, Tensile properties