Multi-material laser powder bed fusion: The effect of cross-contaminations of Cu particles in AlSi10Mg feedstock on the mechanical properties of the part

Cross-contamination after mixing metal powders in multi-material laser powder bed fusion (MMLPBF) is a common production problem and represents a significant barrier to the advancement of this emerging additive manufacturing technology. To assess the effect of such contamination on a key material combination for MMLPBF, the present article examines the effect of cross-contamination of CuCr1Zr foreign particles in AlSi10Mg feedstock on the respective metallurgical and mechanical properties of the final part. Different CuCr1Zr contamination levels were selected, e.g. of 0.5 wt.%, 3.0 wt. % and 5.0 wt.%, respectively, and the test results were compared against the uncontaminated feedstock. The metallurgical structure of CuCr1Zr contaminated samples revealed characteristic Al-rich inclusions. Tensile tests indicate that these inclusions result in material embrittlement and - in general - reduced tensile mechanical properties Quantitative analysis of the tensile test results showed that the quality (consisting of both, tensile strength and deformation capabilities) of printed samples strongly depends on both the contamination level and printing direction. The investigation discusses critical contamination levels for this material combination and explores the potential for powder reusability and in-situ alloying applications.