Effect of boron carbide particle size and volume fraction of TiB–TiC reinforcement on steady state creep behaviour of PM processed titanium matrix composites

Abstract

TiB–TiC reinforced titanium matrix composites (TMCs) were synthesised through pressureless sintering of titanium and boron carbide (B4C) powder compacts. Effect of boron carbide (B4C) particle size and volume fraction of TiB–TiC reinforcement on steady state compression creep behaviour of composites was investigated in the temperature range of 773–873 K. The creep rates of composites are found to be about two orders of magnitude lower than those of unreinforced titanium. The creep rates further lowered with decrease in size of B4C particles (from 16 to 3 μm) used in preparation of composites as well as with increase in volume fraction of the TiB–TiC reinforcement from 10 to 30 vol.%. By using the concept of effective stress as well as incorporation of load transfer and substructural strengthening effect produced by the reinforcement into analysis, the entire creep data of Ti and the composites can be made to merge on to a single line within a scatter band of factor of 2–3 and can be represented by a unified power-law equation.