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

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 Al 9 (Mn,Ni) 2 and Al 3 Ni 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%. T E : 651.81 °C for the non-heat-treated sample and T E :648.79 °C for the heat-treated sample. Fusion enthalpy (Δ H) 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.