P. Ashwath

Effect of ceramic reinforcements on microwave sintered metal matrix composites

ABSTRACT Metal matrix composites (MMCs) using Aluminum Alloy 2900 and 2024 as matrix material with silicon carbide and alumina as reinforcement have been fabricated through powder metallurgy route for investigation. The average particle size of matrix metal and reinforcement material considered in this research is 10 µm. AA-SiC and AA-Al2O3 composites with 3, 6, and 9 weight percentage (wt%) of SiC and Al2O3 are fabricated. The Rockwell hardness and Compressive strength of AA-SiC and AA-Al2O3 composites were found to increase with an increase in the wt% of reinforcement when the samples were microwave sintered. AA 2024 with 6 wt% Al2O3 reinforced MMCs samples were exhibiting improved hardness results, strength behavior, and stress-strain behavior when the samples are microwave sintered. AA 2900 with 6 wt% Al2O3 exhibited good ductility and formability properties. Good Microstructural bonding was observed in the MMCs, which is attributed to finer Al2O3 particulate used as reinforcement and the microwave sintering.

Effect of microwave heat treating processing on frictional behaviour of aluminium alloy 2900 composites

Abstract The sliding wear behaviour of microwave processed, SiCp and Al2O3p reinforced aluminium alloy 2900 and 2024 metal matrix composites prepared by powder metallurgy method was investigated in a pin on disc system. The objective is to determine the effects of novel alloying elements of AA 2900, ceramic addition and microwave aging process on the strength to tribological properties. This composite is evaluated to be an effective replacement for conventionally available AA 2024 composites in brake applications. Compared to conventional heat treating processes, microwave processing used for heat treating the samples is observed to be novel method in improving the strength–microstructural–tribological properties. AA 2900 with 6 wt-% Al2O3 exhibited good strength to microstructure relationship with excellent wear characteristics compared to AA 2024 composites which are governed by alloying elements in AA 2900. 2 H aged AA 2900 with 6 wt-% Al2O3 sample exhibited good frictional coefficient values with good density and strength characteristics. Hence, it is observed that alloying elements in AA 2900 and microwave processing have enhanced the strength to tribological behaviour where the property enhancement is achieved only through ceramic reinforcements.

Ultrasonication and microwave processing of aluminum alloy- Graphene - Al2O3 nanocomposite

ABSTRACT Nanocomposites with Graphene and Al2O3 (particulates) as reinforcement combinations with various proportions (weight percentage) in aluminum alloy AA 2024 and AA 2219 matrix with 30 to 40 µm are processed through vacuum hot press and microwave processing approach. X-ray diffraction and Raman spectroscopy analysis was done on developed nanocomposites to study the Graphene peaks, carbide formation, and other deformation on added Graphene in the nanocomposites during microwave processing. Microstructural, compressive, and diametrical tensile strength analyses were also carried out on developed composites. Effect of Graphene addition in combination with Al2O3, on strengthening mechanism during microwave sintering, had been discussed.

Effect of Precipitation Hardening on Particle Reinforced Aluminum Alloy Composites

In this research work two different composites are manufactured using Aluminum Alloy (AA) 2900 and 2024 as matrix with SiC and Al2O3 as reinforcement material through powder metallurgy technique. The objectives of this research work are to determine the influence of the sintering duration on the properties of composites and to understand the effect of different aging time on the properties of the composites. The weight percentage of reinforcement materials, sintering duration and aging duration were considered as variable parameters in this experimental work. The metal powder and the reinforcement are blended in high energy ball mill and compacted in Universal Testing Machine at a constant load of 500Mpa to fabricate green compacts. The green compacts were subjected to microwave sintering at 500°C for 60 minutes as per the design of experiments. The sintered samples are quenched in water till it reaches the temperature close to room temperature and loaded again into the sintering furnace for artificial aging (for a varying duration of 60 & 120 minutes). This will allow the samples to form CuAl2 and CuMgAl2 precipitates which are confirmed using SEM and X-ray diffraction studies. Hardness studies are carried out using Rockwell and Brinell hardness tester respectively.Copyright