Enhanced mechanical properties of magnesium alloy reinforced by layered Ti3AlC2 MAX phase fabricated by SPS at a near solidus temperature

Abstract

Powder metallurgy stands out as a highly promising and versatile method for manufacturing particle-reinforced metal matrix composite (MMCs) as compared to other fabrication processes. This method ensures excellent binding between the matrix and reinforcement, uniform microstructure, and effectively prevents the formation of undesirable phases. In this study, magnesium alloy (AZ91) metal matrix composites (MMCs) reinforced with 0–30 vol% of Ti3AlC2 MAX phase were prepared by Spark Plasma Sintering (SPS) from powders at temperature close to the solidus. Ti3AlC2 is a member of the MAX phases which are known for their layered structure, machinability and being ternary carbides. The latter was synthetized from pure components (Ti, TiC and Al) using insulated SPS technology at high temperature. Sintered composites reached quasi-full density, as measured by Archimedes’ method. Their microstructure has been assessed by SEM and X-ray diffraction (XRD) respectively. Mechanical properties in relationship with the microstructure of all composites were carefully investigated. The experimental compressive tests data were extracted to obtain true strain-true stress curves. Vickers hardness (HV1), ultimate compressive strength (UCS) and conventional yield strength (0.2%YCS) increase with an increasing fraction of Ti3AlC2 in the composites and compare favorably with literature. SEM observations of fracture surfaces after compression tests seem to show that cracks initiate in both Ti3AlC2 clusters and α-Mg/MAX interfaces.