Effect of laser surface modification on the structure and mechanical properties of Al–8%Ca, Al–10%La, Al–10%Ce, and Al–6%Ni eutectic aluminum alloys

Abstract

Additive manufacturing, which includes a set of technologies for manufacturing complex-shaped products with the required set of properties, is currently widely developed. Most additive technologies are associated with the manufacture of the product by melting and fusion of metal powder particles due to laser irradiation. Al–Ca, Al–Ce, Al–La, and Al–Ni eutectic aluminum alloys featuring excellent casting properties are supposedly promising for use in additive technologies. However, there is very little information on the effect of laser processing on such eutectic structures in the literature. In this regard, the paper investigated the effect of laser irradiation on the structure and mechanical properties of samples made of eutectic compositions, namely Al–8%Ca, Al–10%La, Al–10%Ce, and Al–6%Ni. This was achieved by continuous laser modification of their surfaces. The hardening level was evaluated by measuring the microhardness of the modified surface. The mechanisms of sample fracture under tensile testing were established. It was shown that the distribution of the second component in the structure of modified sample surfaces of all the four alloys becomes more uniform compared to the base metal structure. In the Al–8%Ca alloy, the greatest hardening effect was observed, which, however, contributes to embrittlement under tensile stress. However, the modified Al–8%Ca alloy is of interest because of its increased hardness and possibly increased wear resistance. On the contrary, laser modification of the Al–10%Ce, Al–10%La, and Al–6%Ni alloy sample surfaces provides a lower hardening effect, but increases their tensile strength with the formation of a ductile or mixed ductile-brittle fracture. The results obtained confirm the prospects of using the Al–Ca, Al–Ce, Al–La, and Al–Ni alloys in additive manufacturing.