Influence of High-Productivity Process Parameters on the Surface Quality and Residual Stress State of AISI 316L Components Produced by Directed Energy Deposition

Gabriele Piscopo,Eleonora Atzeni,Alessandro Salmi

doi:10.1007/s11665-021-05954-3

Gabriele Piscopo, Eleonora Atzeni + Show 1 more

Open Access

https://doi.org/10.1007/s11665-021-05954-3

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Abstract

The production of large components is one of the most powerful applications of laser powder-directed energy deposition (LP-DED) processes. High productivity could be achieved, when focusing on industrial applications, by selecting the proper process parameters. However, it is of crucial importance to understand the strategies that are necessary to increase productivity while maintaining the overall part quality and minimizing the need for post-processing. In this paper, an analysis of the dimensional deviations, surface roughness and subsurface residual stresses of samples produced by LP-DED is described as a function of the applied energy input. The aim of this work is to analyze the effects of high-productivity process parameters on the surface quality and the mechanical characteristics of the samples. The obtained results show that the analyzed process parameters affect the dimensional deviations and the residual stresses, but have a very little influence on surface roughness, which is instead dominated by the presence of unmelted particles.

Highlights

In directed energy deposition (DED) processes, a heat source is used to melt-deposited material as it is fed onto a substrate
It has been observed in the literature that the surface quality and distortions are the most challenging issues in the laser powderdirected energy deposition (LP-DED) process (Ref 12-14)
The results are described in terms of surface quality and residual stresses

Summary

Introduction

In directed energy deposition (DED) processes, a heat source is used to melt-deposited material as it is fed onto a substrate. The laser powderdirected energy deposition (LP-DED) process combines a laser beam with powder material. Industrial interest in LP-DED is growing rapidly, especially because of its capability in repairing applications and in the production of large components (Ref 810). Despite the enormous advantages that may be derived from the use of the LP-DED process, its applications is still limited (Ref 11). It has been observed in the literature that the surface quality and distortions are the most challenging issues in the LP-DED process (Ref 12-14). On average, the surface roughness obtained using the LP-DED process is

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