Individual and combined additions of calcium and antimony on microstructure and mechanical properties of squeeze-cast AZ91D magnesium alloy

Bankoti, AKS and Mondal, AK and Kumar, Subodh and Ray, BC (2015) Individual and combined additions of calcium and antimony on microstructure and mechanical properties of squeeze-cast AZ91D magnesium alloy. In: MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, 626 . pp. 186-194.

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Abstract

The effects of combined additions of Ca and Sb on the microstructure and tensile properties of AZ91D alloy fabricated by squeeze-casting have been investigated. For comparison, the same has also been studied with and without individual additions of Ca and Sb. The results indicate that both individual and combined additions refine the grain size and beta-Mg17Al12 phase, which is more pronounced with combined additions. Besides alpha-Mg and beta-Mg17Al12 phases, a new reticular Al2Ca and rod-shaped Mg3Sb2 phases are formed following individual additions of Ca and Sb in the AZ91D alloy. With combined additions, an additional Ca2Sb phase is formed suppressing Mg3Sb2 phase. Additions of both Ca and Sb increase yield strength (YS) at both ambient and elevated temperatures up to 200 degrees C. However, both ductility and ultimate tensile strength (UTS) decrease first up to 150 degrees C and then increase at 200 degrees C. The increase in YS is attributed to the refinement of grain size, whereas, ductility and UTS are deteriorated by the presence of brittle Al2Ca, Mg3Sb2 and Ca2Sb phases. The best tensile properties are obtained in the AZXY9110 alloy owing to the presence of lesser amount of brittle Al2Ca and Ca2Sb phases resulted from the optimum content of 1.0Ca and 0.3Sb (wt%). The fracture surface of the tensile specimen tested at ambient temperature reveals cleavage failure that changes to quasi-cleavage at 200 degrees C. The squeeze-cast alloys exhibited better tensile properties as compared to that of the gravity-cast alloys nullifying the detrimental effects of Ca and/or Sb additions. (C) 2014 Elsevier B.V. All rights reserved.

Item Type:	Journal Article
Publication:	MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
Publisher:	ELSEVIER SCIENCE SA
Additional Information:	Copy right for this article belongs to the ELSEVIER SCIENCE SA, PO BOX 564, 1001 LAUSANNE, SWITZERLAND
Keywords:	Magnesium alloy; AZ91D; Squeeze-casting; Microstructure; Tensile properties; Brittle fracture
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	20 Apr 2015 07:06
Last Modified:	20 Apr 2015 07:06
URI:	http://eprints.iisc.ac.in/id/eprint/51236

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