Effect of Mn on Microstructure and Mechanical Properties of Al-4Ni Alloy

Abstract

The application of aluminum alloys at elevated temperatures has been attractive for decades, and Al-Ni-based alloys have recently been recognized as potential candidates. The effect of Mn on Al-4Ni alloy has been investigated in this work. Addition of Mn transformed the eutectics from Al3Ni/α-Al to Al9(Ni,Mn)2/α-Al phases. Mn also improved the tensile strength at both 25°C and 250°C. The yield strength at 25°C increased from 48 MPa to 92 MPa with 1.87% Mn and then to 117 MPa with 3.77% Mn. At 250°C, the yield strength increased from 35 MPa to 82 MPa with 1.87% Mn and then to 101 MPa with 3.77% Mn. The alloys with Mn also showed less strength loss than Al-4Ni alloy at 250°C. The eutectic Al9(Ni,Mn)2 phase showed good thermal stability. No coarsening was observed after 2000 h at 250°C.