Study of mechanical properties of 2024-RAM2C and 6061-RAM2C aluminium alloys made by laser-based powder bed fusion of metals

Purpose This study aims to present the laser-based powder bed fusion of metals (PBF-LB/m) process development of two alloys, Aluminium 2024-RAM2C and Aluminium 6061-RAM2C, commercialised by Elementum3D, USA, and the results of chemical, metallurgical, static and dynamic mechanical tests of the solid material obtained using the process parameters also developed in this study. Design/methodology/approach A full process development of both alloys was carried out, including not only process parameterisation that yielded a density of >99.9%, but also static and dynamic testing to validate the material properties. As a special feature, dynamic testing was used to demonstrate that different process parameters, although resulting in similar densities, can lead to significant differences in residual stress levels. Findings The preliminary assessment of the material properties indicates that the materials exhibit considerable flexibility in process parameterisation. In addition, the material exhibits an optimum microstructure characterised by a fine and uniform distribution of reinforcing particles. A combination of stress relief and T6 heat treatment (denominated in the paper as Type 2) contributes to the significant increase in hardness, yield and tensile strength through the mechanism of precipitation hardening. However, impact energy, elongation and area reduction remain open for further analysis and research work. Research limitations/implications The fatigue tests were carried out on two alloys and three conditions (three sets of process parameters), which is not sufficient for a conclusive statement on the validity of the dynamic tests as a decisive factor in the selection of the final process parameters. Further studies are therefore required to confirm this hypothesis that has been exposed in this paper. Practical implications Much more extensive characterisation of Aluminium 2024-RAM2C and Aluminium 6061-RAM2C than that found in the literature is offered in this study and contributed to their qualification for a variety of industrial applications. Originality/value This study claims to be a cornerstone for a change in process development in PBF-LB, as the findings indicate the use of fatigue test results before the parameters for an alloy are finally adopted. This would prevent premature failure of AM parts in the application.