The effect of technological parameters on the microstructure and mechanical properties of AlSi₁₇Cu₄ alloy

The mechanical properties (HB, HV, R_0.2, Rm) and plastic properties (A₅, Z) of AlSi₁₇Cu₄ alloy when exposed to chosen technological processes, such as modification, overheating and rapid cooling, are presented in this paper. The best combination of properties was noticed in alloy overheated for 40 minutes at 920 oC and casted into a metallic mould submerged in liquid nitrogen. Moreover, the technological stability and homogeneity of alloys were evaluated based on spread of results, expressed by standard deviation. It was proven, based on microstructure analysis, that the best effect of refinement was achieved by intensive cooling of alloy preceded by its overheating. The XRD analysis indicated that the intermetallic phases, mainly θ(Al₂Cu) and γ₁(Al₄Cu₉) caused hardening of the solution, improvement in mechanical properties and technological stability.