Strengthening of Ti3AlC2 by incorporation of Si to form Ti3Al1−xSixC2 solid solutions

A series of Ti3Al1-xSixC2(x <= 0.25) solid solutions were synthesized using an in situ hot pressing/solid-liquid reaction method. It was revealed that the lattice parameter c decreased dramatically but a remained almost unchanged with an increase of Si in the Ti3Al1-xSixC2 solid solutions. A relationship between lattice parameter c (in nm) and Si content x, c(x) = 1.8541 - (8.5674 x 10(-2))x, was established. A significant strengthening effect was observed when x was greater than 0.15 in the Ti3Al1-xSixC2 solid solutions: the Vickers hardness, flexural strength and compressive strength were enhanced by 26%, 12% and 29%, respectively, for Ti3Al0.75Si0.25C2 solid solution. The electrical resistivities of Ti3Al1-xSixC2 solid solutions were in the range 0.35-0.37 mu Omega m and increased slightly with an increase of Si content. The addition of Si to Ti3AlC2 to form solid solutions had no deleterious effect on the oxidation resistance at 1100 degrees C due to the formation of a continuous Al2O3 layer. (c) 2005 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.