Mechanical properties and microstructure of in situ formed Ti₂AlN/TiAl(WMS) composites

The Ti₂AlN-reinforced TiAl (WMS) composites with different contents of Ti₂AlN were prepared by an in situ method of reactive arc-melting technique. According to the results of X-ray diffraction (XRD) analysis, the Ti₂AlN-reinforced WMS composites consist of γ-TiAl, α₂-Ti₃Al, and Ti₂AlN phases. Microstructure analysis results indicate that Ti₂AlN reinforcements with rod-like in shape form in the WMS matrix with a α₂/γ lamellar structure containing some bulk γ phases. With volume fraction of Ti₂AlN increasing, the grain size of the composites decreases significantly and the elasticity modulus (E) increases. The compressive strength and compressive fracture strain of the composite with 3 vol% Ti₂AlN have a maximum value of 1,654 MPa and 22.5 %, respectively, which are approximately improved by 45.84 % and 29.31 %, respectively, compared with that of the unreinforced WMS alloy.