Linear Elastic FE-Analysis of Porous, Laser Welded, Heat Treatable, Aluminium High Pressure Die Castings Based on X-Ray Computed Tomography Data.

Fabian Teichmann,Klaus Dilger,Arne Ziemer,Martin Leitner,Jonas Hensel

doi:10.3390/ma13061420

Abstract

The welding of aluminium high pressure die castings is a well known and broadly investigated challenge in various fields of industry and research. Prior research in this specific field mainly focused on the optimisation of the welding and the casting process and on the cause of the frequently occurring porosity and incomplete fusion phenomena, whereas the impacts of these defects have hardly been addressed. Therefore, the underlying study presents the investigation of weldments in EN AC-AlSi10MnMg high pressure aluminium die castings by linear elastic finite element analysis based on X-ray computed tomography as a novel approach. Hereby, four laser weldments with differing surfaces and pore contents were investigated by X-ray computed tomography and tensile testing. Based on the voxel datasets of the porous weldments, triangular finite element meshes were generated and a numerical finite element analysis was conducted. Good agreement of the stress–strain curves between the simulations and the experiments was achieved.

Highlights

IntroductionDefects in Laser Welded Aluminium High Pressure Die Castings
The current study aims to investigate welded aluminium high pressure die castings containing typical defects related to welding by the use of voxel-based finite element simulations
The current study aims to investigate the feasibility of voxel-based structural finite element simulations of complex welded joints in high pressure aluminium die castings containing inner and outer defects related to welding

Summary

Introduction

Defects in Laser Welded Aluminium High Pressure Die Castings. Society [3], the cause of the porosity can be distinguished in metallurgical and mechanical pore formation. In the case of metallurgically formed pores, hydrogen is released into the melt, e.g., by the dissociation of aluminium hydrides, agglomerates within the melt pool and is trapped in the weld metal during the solidification of the melt. In the case of mechanical pore formation, inclusions or pores present within the die casting part are heated rapidly by the laser beam during the welding process. The heat input causes a rapid expansion of the pores, which leads to pore formation in the weld metal, an ejection of the molten metal and/or incomplete fusion. The weldability of high pressure aluminium die castings depends, amongst other factors, on the presence of inclusions and the hydrogen content [4]

Methods

Results

Conclusion