Role of Ti۳AlC۲ MAX phase on characteristics of in-situ synthesized TiAl intermetallics. Part IV: mechanical properties

In this study, the ۴th part of a series of publications on the sintering and characterization of TiAl-Ti۳AlC۲ composite materials, the mechanical properties were measured and discussed. For this purpose, different contents of synthesized Ti۳AlC۲ reinforcement (۱۰, ۱۵, ۲۰, ۲۵, and ۳۰ wt%) were added to metallic Ti and Al powders, then ball-milled and manufactured by spark plasma sintering (SPS) for ۴۲۰ s at ۹۰۰ ºC under ۴۰ MPa. Flexural strength, fracture toughness and Vickers hardness were measured by ۳-point technique, SENB method, and indentation technique, respectively. Increasing the Ti۳AlC۲ content resulted in improvement of the mechanical properties, so that TiAl-۲۵ wt% Ti۳AlC۲ composite showed the best flexural strength and Vickers hardness (۲۷۰ MPa and ۴.۱۱ GPa, respectively). Increasing amount of Ti۳AlC additive had no significant effect on fracture toughness. Densification improvement, in-situ formation of Ti۲AlC, and limitation of grain growth were recognized as the reasons of mechanical properties enhancement. In contrast, further addition of Ti۳AlC۲ (۳۰ wt%) decreased the mechanical properties due to the reduction of density and formation of more Ti۲AlC agglomerates in grain boundaries.

کلیدواژه ها:

SPS ، TiAl-Ti۳AlC۲ ، Flexural strength ، Hardness ، Fracture toughness