Poddar, Palash and Murugesan, A P (2019) Calculation of internal back stress of different gravity-die cast Mg-alloys during creep deformation. Journal of Metallurgy and Materials Science, 61(2) . pp. 61-72.
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The present work confers to the characterization of two as-cast Mg-alloys (Mg8%Sn and Mg-8%Sn-3%Al-1%Si (TAS831)) before and after creep tests in four stress level of 30, 35, 40 and 45 MPa at 150°C. Castings of both Mg-8%Sn and TAS831 alloys are produced using gravity-die casting technique. X-ray diffraction (XRD) is employed to identify the phases present in as-cast Mg-8%Sn and TAS831 alloys. Scanning electron microscopy (SEM) is used to characterise as-cast and crept Mg-8%Sn and TAS831 alloys. XRD analysis and SEM micrographs confirm the presence of α-Mg matrix and Mg2 Sn precipitate in as-cast Mg-8%Sn alloy and occurrence of Mg2 Sn, Mg2 Si, Mg17 Al12 precipitates on the α-Mg matrix in as-cast TAS831 alloy. Image analyses (using Image J software) of the SEM micrographs reveal that both as-cast Mg-8%Sn and TAS831 alloys comprise almost same amount of precipitates (∼6.7 vol. %). Creep strength of as-cast TAS831 alloy is more than that of Mg-8%Sn, due to presence of Mg2 Si as "Chinese Script" morphology in TAS831 alloy. Internal back stress, a resisting force for creep deformation arises from the initial microstructure of precipitation hardened alloy is found same (∼10 MPa at 150°C) for both as-cast Mg-8%Sn and TAS831 alloys. Presence of low melting precipitate, Mg17 Al12 lowers the minimum stress required for creep deformation of as-cast TAS831 alloy at 150°C. True creep exponent (n) differs for as-cast Mg-8%Sn and TAS831 alloys, which signifies different creep deformation mechanism in the matrix of as-cast Mg-8%Sn and TAS831 alloys.
|Uncontrolled Keywords:||Mg-Alloys;Creep;Internal back stress;True creep exponent|
|Divisions:||Material Science and Technology|
|Deposited By:||INVALID USER|
|Deposited On:||04 Oct 2019 14:50|
|Last Modified:||17 Nov 2022 14:41|
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