Mechanical and Microstructural Behavior of Sintered NiAl-Based High Entropy Alloy

Abstract

A high entropy Ni-Al-Ti-Mn-Co-Fe-Cr alloy (HEA) system was fabricated using spark plasma sintering (SPS). The alloys at different elemental compositions were developed at a sintering temperature of 850 °C, a heating rate of 90 °C/min, a pressure of 50 MPa, and a dwelling time of 5 min. The sintered alloys' mechanical characteristics, microstructure, phase evolution, and density were assessed. The evolved microstructure of the sintered HEAs shows a homogenous dispersion of the alloying metals. The sintered microstructures showed a mixture of simple and complex phases. The phase refinement shows that the sintered HEAs exhibited a lower and the least grain size of 2.28 µm compared to the Ni50Al50 alloy having 8.26 µm. Likewise, a higher micro-strain value of 1.25E-1 was attained by the non-equal atomic HEA, while the unalloyed has 1.87E-3. The microhardness value of the sintered alloys varied from 103.5 HV to 139.2 HV, while their measured density varied from 5.23 g/cm3 to 6.44 g/cm3.