Microstructural characterisation of the subsurface plastic zone formed during erosion of A356 AI alloy and composites

Saravanan, RA and Samajdar, I and Surappa, MK (1998) Microstructural characterisation of the subsurface plastic zone formed during erosion of A356 AI alloy and composites. In: Wear, 215 (1-2). pp. 223-231.

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Abstract

An effort was made to characterise the different layers of the plastic zone in eroded A356 alloy and the composite containing 10 vol% SiCp. The plastic zone can be demarcated into four distinct characteristic regions, viz. I-IV, from surface towards bulk. Each region contained its characteristic dislocation substructure: cell/grain size, misoriemation, loose dislocations in the cell/grain interior and micro-texture. With an increase in distance from the top eroded surface, there was a drop in hardness accompanied by an increasing cell size and a decreasing cell misoriemation. The top two regions were random in orientation, while in region III, the micro-texture was strongest with high loose dislocation density. Different regions in the plastic zone were given annealing treatment at $100^0C$ and $200^0C$ and subsequently characterised by TEM. DSC and hardness measurements. Results of these studies indicate that region III containing highest loose/recoverable dislocation density is the least stable. In the composite, regions II and III were observed to contain less loose/recoverable dislocations, but more strain localisation (as compared to the alloy). Higher erosion rate m MMCs can be attributed to higher strain localisation observed in MMCs.

Item Type:	Journal Article
Publication:	Wear
Publisher:	Elsevier
Additional Information:	Copyright of this article belongs to Elsevier.
Keywords:	Erosion;Metal matrix composites;Dislocation substructures;Shear bands;Instabilities in MMCs
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy) Division of Mechanical Sciences > Mechanical Engineering
Date Deposited:	08 Jan 2007
Last Modified:	19 Sep 2010 04:33
URI:	http://eprints.iisc.ac.in/id/eprint/9303

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