Synthesis and characterization of hybrid Al-based matrix composites fabricated by spark plasma sintering

Abstract

The present paper is based on the fabrication and characterisation of Hybrid AMMC. Moving further,.mechanical properties of the fabricated composite materials are also discussed. In the present work, aluminium is taken as the matrix material, and SiC and Al2O3 are the ceramic particles taken as the reinforcements. Weight percentage of reinforcements are limited to 10wt%, where combination of percentage of SiC and Al2O3 are taken as (8 wt%,2 wt%) and, (6 wt%, 4 wt%) respectively .Fabrication of the composites’ samples are done through Powder Metallurgy route. Mechanical milling is done to mix composite powders, and consolidation is done through the Spark Plasma Sintering process. XRD patterns of powders after regular intervals of mechanical milling are discussed. Density of samples consolidated through Spark Plasma Sintering came out more than 97% as opposed to Hot Press, where maximum density achieved was 89%. EDS mapping of composite samples is utilized to show the kind of distribution of reinforcement particles in the aluminium matrix. Results showed that hardness and compressive strength of aluminium is improved by mixing SiC and Al2O3 particles. Study based on the fretting wear of the AMMC samples is also discussed, where characteristics such as the coefficient force and the friction force is discussed..Coefficient of friction graphs for different compositions shows that samples with lesser holding time and higher percentage of SiC in SPS consolidation shows higher COF values. Study of the wear surface based on the SEM images is done after fretting wear of composite samples at two different loads of 20N, 30N with the frequency of 10 Hz, with displacement amplitude of 0.2 mm. Maximum compression strength of 492 MPa and 476 MPa was achieved for Al composites containing reinforcemnt of (8 wt% SiC, 2 wt% Al2O3) and (6 wt% SiC, 4 wt% Al2O3).