Compressive deformation behaviour and toughening mechanisms of spark plasma sintered NiAl-CNT composites

Carbon nanotube (CNT)-reinforced NiAl intermetallic composites were produced via powder metallurgy, particularly spark plasma sintering. The aim of this study was to evaluate the room temperature compressive behaviour of the sintered NiAl-CNT composites with a focus on the toughening mechanisms of the CNT reinforcement and the resulting microstructures. Remarkably, the NiAl-0.5 wt% CNT composites exhibited a balanced combination of strength and toughness despite a trade-off tendency, due to the presence of both coarse and fine bimodal grains in its microstructure. Mechanical properties of 831 MPa, 429 MPa and 360 HV were recorded for the ultimate compressive strength (UCS), compressive yield strength (CYS) and microhardness of the NiAl-0.5%CNT intermetallic composites, respectively, along with a compressive strain of 12% being higher than the unreinforced NiAl.