Mechanical behavior of A356 matrix nanocomposites fabricated using two step mixing via stir casting technique
In this work an investigation of compressive strength and forgeability behavior have been made to explore the effect of SiC nano particles on A356 alloy matrix for the development of A356/SiC nanocomposites using two step mixing through stir casting technique. A356 alloy ingot was selected as a matrix and AFP+SiCn (99.9% pure aluminium fine powder+nano size SiC mechanically forged by using ball mill at 100 rpm for duration of 10 hours) as a reinforcement. Argon gas was used to protect from oxidation during ball milling process. SiC nano particles were varied from 1% to 5% in a step of 1% by weight. In stir casting technique, stirring process was performed at 500±50 rpm for mixing AFP+SiCn in the melt matrix for total stirring period of 10 minutes in two steps. Composites were poured at 680±20° C into the permanent mould. Compressive strength and forgeability tests of fabricated nanocomposites were evaluated by using hydraulic pellet press machine. To analyze the fractured mechanism SEM microstructure was examined. The presence of SiC nano particles were confirmed by EDX spectrum. It was revealed from the results that compressive strength increases with increment of SiC nano particles and found as 603 MPa at 5% SiC nano particles. Whereas forgeability of the nanocomposites were decreased with the increment of SiC nano particles. SEM micrographs showed the ductile fractured mechanism was dominant over the brittle fracture. The main constituents present in the nanocomposites were verified by EDX spectrum.
Fibre reinforcements for composite materials and electron microscopy
2014 Composites depend for most of their properties on the reinforcing fibres which usually have diameters of the order of 10 03BCm. These fibres can be mechanically evaluated but an understanding of the processes controlling their behaviour must use transmission electron microscopy to study mechanism at the atomic level. All classes of synthetic fibre are discussed in this paper. Microsc. Microanal. Microstruct. 2 (1991)
Developments in the processing and properties of particulate Al-Si composites
In the past ten years, materials R&D has shifted from monolithic to composite materials, adjusting to the global need for reduced weight, low cost, quality, and high performance in structural materials. This article reviews developments in the molten processing of particulate Al-Si alloy composites and their respective properties. Existing and emerging processing innovations are discussed, and the reinforcement phases in prominent R&D activities are identified. The vortex (or mixing) method continues to be the most popular processing method in use because of its ease of operation, total production cost, and suitability, while the infiltration, compocasting (or rheocasting), in-situ, and spray atomization and codeposition techniques receive less attention.