Title: Microstructural and hardness study of stir-casted AZ91D/B₄C MMCs

Authors: Sakshi Singh; Nathi Ram Chauhan

Addresses: Department of Mechanical and Automation Engineering, Indira Gandhi Delhi Technical University for Women, Kashmere Gate, Delhi-110006, India ' Department of Mechanical and Automation Engineering, Indira Gandhi Delhi Technical University for Women, Kashmere Gate, Delhi-110006, India

Abstract: This paper investigates the effect of the amalgamation of reinforced based metal matrix composites by using vacuum-based stir casting process. AZ91D Mg alloy is the matrix material and B₄C with varying volume ratio fractions (2, 4, and 6%) act as reinforcement. For microstructural observation, specimens have been machined, polished and then etched. Vickers macro hardness has been evaluated under room temperature. The improvement in macro-hardness has been found in reinforced B₄C/AZ91D MMCs as compared to cast-AZ91D Mg alloy. The microstructural study reveals the enhancement in homogeneity of AZ91D MMCs due to the addition of B₄C reinforcement. The heterogeneous formation of α-Mg matrix and Mg₁₇Al₁₂ has been found to be dominant in the form of dendrite-like three-dimensional branches. The reduction in porosity and voids (microstructural defects) have been observed in B₄C/AZ91D MMCs by vacuum-based stir casting as compared with cast-AZ91D Mg alloy.

Keywords: AZ91D Mg alloy; matrix; boron carbide particles; reinforcement; scanning electron microscope; hardness; phases etc.

DOI: 10.1504/IJMMP.2018.097783

International Journal of Microstructure and Materials Properties, 2018 Vol.13 No.6, pp.439 - 446

Received: 15 May 2018
Accepted: 23 Aug 2018
Published online: 09 Feb 2019 *

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