Achieving balanced high-temperature strength and plasticity of Ti₂AlC/TiAl composite with duplex microstructure

In this work, a duplex-structured Ti₂AlC/TiAl composite consisting of equiaxed γ-TiAl and lamellar colony (α₂+γ) was successfully fabricated by high pressure (120 MPa) spark plasma sintering (SPS), using Ti-48Al-2Nb-2Cr alloy and graphene oxide. Notably, micron-Ti₂AlC particles formed at grain boundaries, while nano-Ti₂AlC particles precipitated at α₂/γ lamellae interfaces. The TiAl composite achieved a superior high temperature strength and ductility. Typically, TiAl composite showed an ultimate tensile strength of 533.7 MPa and an outstanding fracture strain of 8.6 % at 800 °C, improved by 32.8 % and 56.4 %, respectively compared to that of TiAl alloy (ultimate tensile strength: 401.9 MPa, fracture strain: 5.5 %). This enhancement in strength and ductility was mainly attributed to the particle precipitating strengthening, interfacial strengthening, and particle pulling-out and bridging effects.