Influence of Heat Treatment on the Mechanical Properties and Damage Development in a SiC/Ti-15-3 MMC

Abstract

Titanium alloys are commonly heat-treated to meet specific design requirements. In an effort to possibly create a better composite, the influence of heat treatments on the damage evolution and strength of a SiC/Ti-15-3 metal matrix composite (MMC) was studied. Heat treatments of 450°C and 700°C for 24 hours were performed on axial and transverse unidirectional specimens. These specimens, in addition to specimens in the as-received condition, were tested under nonproportional loading paths and then microstructurally analyzed to determine the induced damage. The axial composite with the 450°C heat treatment showed the highest elastic modulus and the lowest stiffness reduction than the other heat treatment conditions. The transverse composite in the as-received condition showed the highest room temperature elastic modulus and the lowest stiffness reduction compared with other heat treatment conditions. Typical damage modes of Ti MMC’s, such as fiber/matrix debonding and matrix microcracking, were seen in all heat treatments. A micromechanics model based on the Mori-Tanaka averaging scheme was implemented to simulate the effects of micro-cracking induced damage on composite stiffness reduction. [S0094-4289(00)01101-4]