Effect of Shot Peening Strengths on Microstructure and Mechanical Properties of 316L Stainless Steel Prepared by 3D Printing

Abstract

Herein, the influence of shot peening (SP) on the microstructure and mechanical properties of 3D printed 316L stainless steel is studied by optical microscopy (OM), electron backscattered diffraction (EBSD), and mechanical properties testing. The changes in microstructure and mechanical properties of 316L stainless steel by 3D printing under different SP strengths are explored, which are drawn as follows: 1) the microstructure of 3D‐printed 316L stainless steel is greatly refined, and the thickness of ultrafine microstructure in the surface layer increases from 0 to 112.5 μm with the increase in peening strengths from 0 to 0.4 MPa; 2) with the increase of peening strengths from 0 to 0.4 MPa, the hardness increases from 236 to 518 HV, and yield strength increases from 547.3 to 740.7 MPa; and 3) based on the EBSD results, the enhanced hardness and yield strength are caused by refinement hardening and dislocation hardening for the SP samples. In addition, it should be noted that the SP decreases the elongation of 3D‐printed 316L stainless steel up to 9%, and makes the ultimate tensile strength reach the maximum value of 871.2 MPa at 0.2 MPa SP strength.