Effect of Sintering Mechanisms on the Mechanical Behaviour of SiC and Kaoline Reinforced Hybrid Aluminium Metal Matrix Composite Fabricated through Powder Metallurgy Technique

Abstract

Hybrid metal matrix composites with naturally available and low-cost reinforcements made tremendous demand in the automobile industry to fabricate parts like Pistons, Automobile body and brake discs because of the superior properties of HMMC compared to monolithic Aluminium. Present work focusses on the fabrication of Al-10% SiC-4% Kaoline HMMC by using conventional sintering, Microwave sintering and Spark Plasma Sintering (SPS) techniques. To reveal the phase identi cation and the distribution of reinforcements, Fabricated composites were investigated by using XRD, SEM integrated with an EDS analyser. Tensile, Compression and hardness tests were performed as per ASTM standards to study the effect of sintering mechanisms on the fabricated HMMC specimens. Results reveal that an enhancement of 13.3 % in U.T.S and 11.7 % Compression strength was observed in the Spark Plasma Sintered HMMC when compared to conventional sintered composite specimens because of lesser sintering temperature, time and the absence of intermetallic compounds in the Spark Plasma Sintering process. The formation of the Al 2 Cu intermetallic compound was identi ed in the XRD pattern of conventionally sintered Al-10% SiC-4% Kaoline HMMC sample due to the high sintering time and temperature which leads to inadequate mechanical properties. The fractured surface of tensile specimens reveals the presence of cleavages on the conventionally sintered HMMC which conforms the brittle fracture, and the existence of dimples on the Microwave sintered and Spark Plasma Sintered samples which signify that the ductile mode of failure in HMMC samples. Out of the three sintering techniques, Spark Plasma Sintering exhibits superior mechanical properties and lesser porosity levels.

Influence of microwave sintering temperatures on mechanical and microstructural Behavior of Al/SiC/snail shell hybrid composite synthesized through powder metallurgy technique

“…The interstitial void spaces present between the matrix and reinforcements are locked with these agglomerations and decreasing the interface bonding between neighboring particles and hinder the movement of dislocations across the grain boundaries, which reduces the strength of the composite. 10,25 As the agglomerations and reinforcement powders have different deformation capacities, triaxial stresses are generated during the loading condition. These triaxial stresses create uneven expansions at the interfaces and generate dislocation defects when the cold compacts undergo a sintering process, which in turn deteriorates the ductility of the composite.…”

“…With an increase in the SiC wt % from 2 wt% to 6 wt%, the U.T.S and compression strength were found to be increased and the maximum U. composite. 10,25 As the agglomerations and reinforcement powders have different deformation capacities, triaxial stresses are generated during the loading condition. These triaxial stresses create uneven expansions at the interfaces and generate dislocation defects when the cold compacts undergo a sintering process, which in turn deteriorates the ductility of the composite.…”

“…3,9 In the SPS technique, the presence of higher sintering rates, less sintering temperature and simultaneous application of quasistatic pressure during sintering enhance the intensity of interface bonding and hence the mechanical characteristics of the composite are improved. 10 In the SPS process, as the high pulsed current passed through the composite, the powder particles underwent joul heating which was prone to partial melting of the outer surface of the particles. This phenomenon makes the highly densified composite at the lower sintering time.…”

Ceramic particles reinforced copper matrix composites manufactured by advanced powder metallurgy: preparation, performance, and mechanisms

“…Therefore, the SPS-fabricated samples exhibit much higher compactness, hardness, strength and wear resistance than the pressureless sintered counterparts. Venkatesh and Deoghare [56] studied the effects of conventional sintering and SPS techniques on the sintering mechanism and mechanical properties of ceramic reinforced metal matrix composites. Compared with the conventional sintered composites, the SPS-fabricated composites exhibit 13.3% higher tensile strength and 11.7% higher compressive strength.…”

Effect of Variations in Microwave Processing Temperatures on Microstructural and Mechanical Properties of AA7075/SiC/Graphite Hybrid Composite Fabricated by Powder Metallurgy Techniques

“…In various powder metallurgical processes, the microwave and spark plasma sintering (SPS) techniques employ unique features such as low sintering temperatures, low sintering periods, and rapid heating rates, which ultimately improve the overall properties of the composite materials [21]. Free-energy of the system has to be reduced in order to start the sintering process, and thereby, the mass transportation kinetics can improve the sintering e ciency due to the improved diffusion process, which eventually leads to the effective transfer of atoms in the crystalline solids.…”