Structural characterisation of unique core-shell shaped Al3Ni2/Al3Ni in-situ intermetallic in Al–4Cu-xNi via powder metallurgy (P/M)

Abstract

An in-situ powder metallurgy technique was used to create Ni–Al3Ni/Al3Ni2 core-shell-shaped aluminum-based intermetallic reinforced composites. The impact of Ni addition on the phase composition, microstructure, and mechanical characteristics of the Al–4Cu-xNi (x = 0, 2, 4, 6, 8, 10 wt%) with respect to various sintering temperatures were examined. Microstructure progression was extensively studied using XRD, and SEM-EDX, and TEM techniques. Initial sintering condition witnessed the proliferation of “Single Core-Shell” structures, comprising Ni as core with Al3Ni2 intermetallic, whereas sample sintered at 620 °C, “Single Core-Shell” and “Double Core-Shell” type of structures containing Al3Ni2, Al3Ni intermetallic were formed between the Al matrix and Ni reinforcements. The 10 wt% Ni addition sample results in substantially high hardness and strength, as compared to the literature, due to the presence of various intermetallics such as Al2Cu, Al3Ni2, and Al3Ni and strong adherence between the formed phase and α-Al matrix. High compressive yield strength of 198.13 MPa and ultimate strength of 410.68 MPa with 24% total elongation was achieved for 10 wt% Ni sample, whereas there was an increase in hardness value of 124.21HV which is 2.4 times higher than that of base Aluminium.