Preparation and mechanical properties of TiCx-Ni3(Al,Ti)/Ni composites synthesized from Ni alloy and Ti3AlC2 powders

In this work, a novel TiCx-Ni-3(Al,Ti)/Ni alloy composite was successfully synthesized from Ti3AlC2 (20 vol% and 40 vol%) and Ni starting powders via in-situ hot-pressing route at 1200 degrees C under 30 MPa. As the interleaved Al atoms diffused out from Ti3AlC2 nanolayers, Ti3AlC2 decomposed into nonstoichiometric nano-TiCx particles while the additional Al and fractional Ti atoms reacted with Ni matrix to form Ni-3(Al,Ti). Due to the homogeneous distribution of ultrafine TiCx and Ni-3(Al,Ti) particles in Ni matrix, Hardness, flexural strength and fracture toughness of the composite reinforced with 20 vol% of Ti3AlC2 increased 50%, 50% and 70%, in comparison with the pure Ni alloy prepared under the same condition. In addition, the positive temperature dependence of flexural strength was detected in 40vol%Ti3AlC2-Ni alloy sample in the temperature range of 20 degrees C and 700 degrees C, and the maximum of flexural strength could reach 989 +/- 28 MPa at 700 degrees C.