Acta Metallurgica Sinica (English Letters) ›› 2022, Vol. 35 ›› Issue (3): 453-465.DOI: 10.1007/s40195-021-01323-0

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Microstructure and Mechanical Properties of B-Bearing Austenitic Stainless Steel Fabricated by Laser Metal Deposition In-Situ Alloying

Sheng Huang1, Xiaoyu Zhang1, Dichen Li1(), Qingyu Li2   

  1. 1State Key Laboratory for Manufacturing Systems Engineering, Xian Jiaotong University, Xian, 710049, China
    2Science and Technology on Reactor System Design Technology Laboratory, Nuclear Power Institute of China, Chengdu, 610213, China
  • Received:2021-06-15 Revised:2021-08-26 Accepted:2021-09-02 Online:2021-11-12 Published:2021-11-12
  • Contact: Dichen Li
  • About author:Dichen Li, dcli@mail.xjtu.edu.cn

Abstract:

In the field repair application of laser metal deposition (LMD), the kinds of powder materials that can be used are limited, while the equipment components are made of various materials. Hence many components have to be repaired with heterogeneous materials. However, it is difficult to match the mechanical properties between the repaired layer and the substrate due to the different materials. Based on the high flexibility of raw materials and processes in LMD, an in-situ alloying method is proposed herein for tailoring the mechanical properties of LMDed alloy. Using different mixing ratios of Fe314 and 316L stainless steel powders as the control parameter, the microstructure and mechanical properties of B-bearing austenitic stainless steel fabricated by LMD in-situ alloying with different proportions of Fe314 and 316L particles were studied. With the increase in the concentration of 316L steel, the volume fraction of the eutectic phase in deposited B-bearing austenitic stainless steel reduced, the size of the austenite dendrite increased, the yield strength and ultimate tensile strength decreased monotonically, while the elongation increased monotonically. Moreover, the fracture mode changed from quasi-cleavage fracture to ductile fracture. By adding 316L powder, the yield strength, tensile strength, and elongation of deposited B-bearing austenitic stainless steel could be adjusted within the range of 712 MPa-257 MPa, 1325 MPa-509 MPa, and 8.7%-59.3%, respectively. Therefore, this work provides a new method and idea for solving the performance matching problem of equipment components in the field repair.

Key words: Additive manufacturing, Laser metal deposition, In-situ alloying, B-bearing austenitic stainless steel, Mechanical properties