PBF-LB Process-Induced Regular Cavities for Lightweight AlSi10Mg Structures.

Victor Lubkowitz,Frederik Zanger,Jonas Alber

doi:10.3390/ma14216665

Abstract

In powder bed fusion with laser beam (PBF-LB), two process-induced defects by pore formation are known: local spherical pores by the keyhole effect and geometrically undefined pores caused by lack of fusion. Both pore types are heterogeneously distributed and can be used for lightweight or damping design applications. The achievable porosity is limited to around 13%. This article presents a novel process-controlled method enabling the targeted and reproducible manufacturing of solid parts with regularly distributed cavities, currently up to 60% porosity in AlSi10Mg, using the balling effect. This eliminates the need for time-consuming digital pre-processing work.

Highlights

In powder bed fusion with laser beam (PBF-LB), two process-induced defects by pore formation are known: local spherical pores by the keyhole effect and geometrically undefined pores caused by lack of fusion
This article presents a novel process-controlled method enabling the targeted and reproducible manufacturing of solid parts with regularly distributed cavities, currently up to 60% porosity in AlSi10Mg, using the balling effect
Foams are used for energy absorption as they allow large deformations at almost constant stress and have great damping properties due to their high number of gas- or powder-filled cavities [3]

Summary

Introduction

Porous structures have been used successfully for many years in the form of metallic foams with porosities of around 50%. Foams are used for energy absorption as they allow large deformations at almost constant stress and have great damping properties due to their high number of gas- or powder-filled cavities [3]. They are well suited as fine filters due to their good particle retention in combination with the mechanical properties [4]. A strong disadvantage of them is the high computational cost required for meshing and mapping large numbers of units, making CAD files hard to operate with [7] For this purpose, it is favorable to be able to generate process-related pores in a stable and regular manner by choosing process parameters without additional computations. Humping and balling weld tracks are of particular interest

Mechanisms of Pore and Weld Track Formation

Lack of Fusion Pores

Weld Track Formation

Production of Regular Cavity Volume Teesst SSppeecciimmeennss

Findings

Conclusions