Study of TiAl alloys and powders produced by infiltration combustion synthesis (ICS)

TiAl alloy and powders with high purity and low oxygen contents were synthesized by ICS. Its densification was studied by both hot isostatic pressing (HIP) and conventional press-sintering process. The samples, with density of more than 3.75 g/cm³, were obtained by HIP at 196 MPa and 1250 °C for 3 h. The microstructure consisted of equiaxed grains and a small volume fraction of lamellar structure. The compressive tests showed the yield strength of TiAl sample is 646 MPa, the compressive strength is 1579 MPa and compressive ductility is above 26%. The addition of Mn and Cr changed the structure, and increased the volume of α₂ phase. The density of powder compact sintered directly might reach the value of theoretical density.