Characterization of Titanium Metal Matrix Composites (Ti-MMC) Made Using Different Manufacturing Routes

Abstract

The mechanical and morphological properties of the unidirectional metal matrix composite (MMC) in titanium alloy reinforced with continuous silicon carbide (SiC) fibres are investigated. The lay-up manufacturing process known as the Foil / Fibre (FF) lay-up was compared with the matrix-coated-fibre (CF) method which promises a better final shape of the reinforcing fibre net. Tensile tests were performed to measure mechanical performance of the manufactured MMCs both longitudinally and transversely respect to the direction of SiC fibres. Elastic behaviour of the investigated MMCs was assumed orthotropic and related to mechanical properties and spatial distribution of the MMC constituents: SiC fibres and Titanium (Ti) matrix. This was achieved using micromechanical modelling based on Finite Element (FE) calculations. FE micromechanical modelling was carried out on the Representative Elementary Volume (REV) of the MMC microstructure resolved by non-destructive analysis such as X-Ray tomography. The analysis carried out highlighted and justified mechanical performance difference between composite laminates containing the same amount of SiC reinforcement fibres for unit of volume but made following different manufacturing routes. To compute overall orthotropic behaviour of the MMC laminate, each constituent was assumed as an elastic isotropic heterogeneity during the averaging. This simplify assumption was validated by comparison with experimental data during the mechanical characterization of the investigated MMC composites.