Effect of heat treatment on microstructure of near-eutectic Al-Ni-Mn alloy, and determination of mechanical and thermoelectrical properties

Abstract

Abstract This study examined the impact of solution heat treatment on the microstructure, mechanical characteristics, thermophysical properties, and electrical resistivity of an Al-Ni-Mn near-eutectic alloy. The investigation focused on varying temperatures and holding periods. The composition of the Al-Ni-Mn near-eutectic alloy system was chosen as Al-5.3%Ni-1.0%Mn (wt). In the non-heat-treated sample, the matrix phase (α-Al) is in equilibrium with the intermetallic Al9(Mn,Ni)2 and Al3Ni phases. The hardness value of the non-heat-treated sample (49.8 kg mm−2) increased to 70.1 kg mm−2 with 2 h of solution heat treatment at 570 °C and then 8 h of artificial aging at 180 °C. The hardness value increased by approximately 41%. TE: 651.81 °C for the non-heat-treated sample and TE:648.79 °C for the heat-treated sample. Fusion enthalpy (ΔH) value was determined as 336.79 (J g−1) for the non-heat-treated sample and 516.36 (J g−1) for the heat-treated sample. Heat Capacity (Cpl) value was found to be 0.364 J g−1.K for the non-heat-treated sample and 0.560 J g−1.K for the heat-treated sample. The electrical resistivity value of the 2 h’ solution heat-treated sample at 600 °C reached its highest value.