Experimental and Numerical Investigations of In Situ Alloying during Powder Bed Fusion of Metals Using a Laser Beam

Andreas Wimmer,Michael F Zaeh,Stefan Adami,Fabian Hofstaetter,Baturay Yalvac,Nikolaus A Adams,Christopher Zoeller

doi:10.3390/met11111842

Abstract

Powder Bed Fusion of Metals using a Laser Beam (PBF-LB/M) is increasingly utilized for the fabrication of complex parts in various industrial sectors. Enabling a robust and reproducible manufacturing process is one of the main goals in view of the future success of PBF-LB/M. To meet these challenges, alloys that are specifically adapted to the process are required. This paper demonstrates the successful interplay of simulation studies with experimental data to analyze the basic phenomena of in situ alloying. The meshless Smoothed-Particle Hydrodynamics (SPH) method was employed for the numerical simulation of two-component powder systems considering both thermodynamics and fluid mechanics in the solid and the melt phase. The simulation results for the in situ alloying of stainless steel 316L blended with the aluminum alloy AlSi10Mg were enriched and validated with the data from a novel experimental test bench. The combination of both approaches can enhance the understanding of the process for in situ alloying. Therefore, future investigations of the PBF-LB/M process with multi-component powder systems can benefit from detailed numerical studies using SPH.

Highlights

Introduction and State of the ArtInitially employed for rapid prototyping only, Powder Bed Fusion of Metals using a Laser Beam (PBF-LB/M) recently achieved a technology-readiness level suitable for series production [1]
The simulation results demonstrate that the Smoothed-Particle Hydrodynamics (SPH) method is capable of reproducing the fundamental physical phenomena, which results in overall good agreement with the experimental data
This paper presents a framework to investigate the basic phenomena of the in situ alloying of stainless steel 316L with the aluminum alloy AlSi10Mg during PBF-LB/M

Summary

Introduction

Introduction and State of the ArtInitially employed for rapid prototyping only, Powder Bed Fusion of Metals using a Laser Beam (PBF-LB/M) recently achieved a technology-readiness level suitable for series production [1]. In addition to its almost unrestricted geometrical design possibilities, a major advantage compared to the traditional manufacturing processes is the easy access to customized powders. Tailored material combinations allow one both to control the printing process and to improve the particular part characteristics, such as the strength, the hardness, and the corrosion behavior [2]. There have been just a few commercially available alloys on the market [3], and most of these alloys were originally designed for conventional manufacturing processes such as forging and drawing only. The PBF-LB/M process is characterized by a high energy input in a small volume resulting in unstable melt pools and rapid solidification. Alloys that are designed for the process are able to improve the melt pool stability or alter the melting and the solidification behavior. Montero-Sistiaga et al [6] showed that adding 4 wt.% silicon to the aluminum alloy 7075 significantly reduced the number of microcracks

Methods

Results

Conclusion