Synthesis & Characterization of Al-Ti-Cr MMC as friction material for disc brakes application

Abstract

A stir die casting coupled with chill casting technique was used to prepare the Al-Ti-Cr composite with variable percentage of SiC and B4C particles. The electrolytic grade of 300 mesh powder was added in the molten of commercially master alloy of Al-Ti-Cr by the simultaneously addition of SiC and B4C. The SiC and B4C in the composite are varied from 0 to 10wt%.The developed composite were characterized using a Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD). F.T.I.R. in corroboration with X.R.D,which confirms the crystallization of corundum (α-Al2O3) as one of the alumina phases.The presence of hard phase in the composite not only improved the ultimate tensile strength, 0.2% proof stress and the hardness of AMC composite. The ductility showed the adverse effect with increase of the SiC and B4Cin the matrix. The results from microstructure confirms the presence of second phase particles at the grain boundaries of aluminium-rich phase as well as within the grain itself which was confirmed by EDAX as well as XRD analysis. These composite have also been subjected to wear and frictiontesting at different operating parameters. Result shows that with increase in wt% of SiC and B4C from 2-10%, the ultimate strength and elongation percent of the Al-Ti-Cr alloy are still higher than that of monolithic alloys. Micro-structural characterization by using SEM depicted that the particles tend to be more agglomerated along with Al2O3 content, confirmed with FTIR analysis. The AFM results revealed that the surface roughness value of the composite is reduced by a factor of ∼3 μm. The results from microstructure showed the presence of second phase particles at the grain boundaries of aluminium-rich phase as well as within the grain itself which was confirmed by FTIR, XRD, AFM and EDAX.