Comparison of titanium silicide and carbide reinforced in situ synthesized TiAl composites and their mechanical properties

Abstract

This study explored a synthesizing route involving in situ development of reinforcements of titanium silicides in a series of TiAl-based matrices. The main features of this processing route are: (1) Incorporating a small quantity of mechanically alloyed Ti–Al–Si and Ti–Al–Si–C powders, referred to as precursors, into Ti–Al–X (X stands for Cr, Mn, Nb, or their combination) powder mixtures that act as matrices; and (2) Hot isostatic pressing (HIPing) of the cold compacted mixture at a temperature of 1100 °C for 4 h. A series of composites based on different Ti–Al–X matrix were synthesized. The structural evolution in these composites was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The mechanical properties and compression tests at room and elevated temperatures (600 °C and 800 °C) have been investigated. In addition, the influence of alloying elements in the matrix has been evaluated from their stress–strain responses.