Microstructure and Mechanical Properties of Dual Scaled NbC/Ti2AlC Reinforced Titanium–Aluminum Composite

Abstract

A TiAl composite containing hybrid particles and whisker reinforcements is fabricated by vacuum melting. The results of this study show that the comprehensive mechanical properties and refining effect of the material are best when the content of reinforcement is 1 wt.%, and then the mechanical properties begin to deteriorate as the content increases further. Finely dispersed NbC particles and uniformly dispersed Ti2AlC whiskers are the ideal second phases. The synergistic strengthening effect of NbC particles and in situ Ti2AlC whiskers are key to the improvement of mechanical properties. Compared with the TiAlNb matrix, the fracture stress/strain of the composite at 1073 K is improved from 612 MPa/19.4% to 836 MPa/26.6%; the fracture toughness at room temperature is improved from 18.8 MPa/m2 to 27.4 MPa/m2.