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

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/alpha-Al to Al-9(Ni,Mn)(2)/alpha-Al phases. Mn also improved the tensile strength at both 25 degrees C and 250 degrees C. The yield strength at 25 degrees C increased from 48 MPa to 92 MPa with 1.87% Mn and then to 117 MPa with 3.77% Mn. At 250 degrees 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 degrees C. The eutectic Al-9(Ni,Mn)(2) phase showed good thermal stability. No coarsening was observed after 2000 h at 250 degrees C.

Automated summary

This study found that the addition of Mn can enhance the tensile strength of Al-Ni alloys, especially at high temperatures, and the eutectic phase Al-9(Ni,Mn)2 exhibits good thermal stability.