Production and characterization of niobium toughened Ti-TiAl₃ metallic-intermetallic composite

Ti-TiAl₃ in situ composites with 10 wt.% Nb were successfully prepared from Ti, Al, and Nb metallic powders by powder metallurgy processing technique of electric current activated/assisted sintering. The current and process time used for producing metallic-intermetallic composites were 2000 A and 90 s, respectively. In terms of fracture toughness, effects of addition of ductile niobium phase to Ti-TiAl₃ composites were investigated. According to SEM-EDS and XRD results, the synthesized composites mainly consisted of TiAl₃ matrix and dispersive Nb reinforcing phases, as well as ductile Ti phases. Hardness and fracture toughness values of the samples were measured by Vickers hardness tester under loads of 100 g and 10 kg, respectively. Fracture toughness value of TiAl₃ intermetallic composites was increased with Nb ductile phase addititon from 1.69± 0.05 MPa m^{1/2} to 5.23± 0.3 MPa m^{1/2}.