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Microstructural evolution of die-cast and homogenized AZ91 Mg-alloys during dry sliding condition

Chelliah, Nagaraj M and Kumar, Ram and Singh, Harpreet and Surappa, MK (2017) Microstructural evolution of die-cast and homogenized AZ91 Mg-alloys during dry sliding condition. In: Journal of Magnesium and Alloys, 5 (1). pp. 35-40. ISSN 22139567

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Official URL: https://doi.org/10.1016/j.jma.2017.02.001


Microstructural evolution of die-cast and homogenized AZ91 Mg-alloys was investigated during dry sliding wear condition. Tribological tests were performed using a pin-on-disc (EN8 steel) configuration with a normal load of 50 N at a constant sliding speed of 2.5 ms−1 under ambient environment. Delamination was recognized as a predominant wear mechanism in both of these materials. The die-cast AZ91 Mg-alloy exhibits lower coefficient of friction and higher wear rate. This can be ascribed to increase in the intensity of load bearing capacity of hard β-Mg17Al12 phase, and crack formation/de-cohesion at the interface between primary α-Mg and discontinuous β-Mg17Al12 phases. On the contrary, the homogenized AZ91 Mg-alloy experiences higher coefficient of friction and lower wear rate. The friction-induced microstructural evolution (supersaturated α-Mg to eutectic (α + β-Mg17Al12)) tending to minimize the wear rate by providing barrier to material removal in the near surface region of homogenized AZ91 Mg-alloy. Therefore, experimental observation revealed that an inverse relationship exists between wear rate and coefficient of friction for the investigated materials. The analysis of worn surfaces and subsurfaces by electron microscopy provided evidence to delamination wear and microstructural evolution.

Item Type: Journal Article
Publication: Journal of Magnesium and Alloys
Publisher: National Engg. Reaserch Center for Magnesium Alloys
Additional Information: The copyright for this article belongs to the Authors.
Keywords: Delamination; Heat treatment; Mg-alloys; Microstructural evolution; Subsurface; Wear rate
Department/Centre: Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited: 31 May 2022 04:36
Last Modified: 31 May 2022 04:36
URI: https://eprints.iisc.ac.in/id/eprint/72850

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