# Enhancing the Mechanical Performance of Laser Powder Bed Fusion Prepared 316L Stainless Steel by Deformation Post-Processing at Ambient Temperature

## TL;DR

This paper shows how deforming 316L stainless steel after 3D printing can significantly improve its strength while keeping good flexibility.

## Contribution

The study introduces ambient temperature deformation post-processing to enhance the mechanical properties of 3D-printed 316L stainless steel.

## Key findings

- Ambient temperature rotary swaging eliminates residual porosity and refines the microstructure of 316L stainless steel.
- Swaging increases ultimate tensile strength from 282 MPa to over 1400 MPa while maintaining elongation to failure above 30%.
- Swaging degree affects the balance between strengthening and softening processes, influencing strength/plasticity ratio.

## Abstract

Preparation of metallic materials via laser powder bed fusion has gained high popularity primarily due to the versatility of the processed materials and the complexity of the available component geometries. However, the prepared components feature characteristic shortcomings. Among the ways to successfully reduce/eliminate printing issues and homogenize the properties within additively prepared materials is optimized post-processing. In this study, we present the positive effects of deformation post-processing at ambient (room) temperature on the microstructure and mechanical properties of AISI 316L stainless steel prepared by laser powder bed fusion. The post-processing was performed by the industrially applicable method of rotary swaging, for which varying swaging degrees were applied. The selected swaging degree influenced primarily the interactions between the dynamic strengthening and softening processes and consequently the strength/plasticity ratio, although all the applied swaging degrees successfully eliminated the residual porosity and imparted (sub)structure development and grain refinement. The ultimate tensile strength (UTS) for the original workpiece was 282 MPa, and it increased up to more than 1400 MPa after the final swaging while maintaining favorable plasticity (elongation to failure over 30%). The study thus proposes a way to successfully enhance the performance of additively manufactured AISI 316L steel with the use of a commercially applicable plastic deformation technology.