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Microstructural modification of Sn–Bi and Sn–Bi–Al immiscible alloys by shearing / Z. Cassinath, Z. Li, S. Sridhar, A. Das, H. R. Kotadia, Amit Das

Materials Science and Technology, Volume: 35, Issue: 18, Pages: 2157 - 2164

Swansea University Author: Amit Das

Abstract

Sn–20 wt-%Bi and immiscible Sn–20 wt-%Bi–1 wt-%Al alloys were used to understand the effect of high-intensity shearing on microstructural refinement. Novel ACME (Axial Centrifugal Metal Expeller) shearing device, based on axial compressor and rotor–stator mechanism to generate high shear rate and in...

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Published in: Materials Science and Technology
ISSN: 0267-0836 1743-2847
Published: Informa UK Limited 2019
Online Access: Check full text

URI: https://cronfa.swan.ac.uk/Record/cronfa51938
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Abstract: Sn–20 wt-%Bi and immiscible Sn–20 wt-%Bi–1 wt-%Al alloys were used to understand the effect of high-intensity shearing on microstructural refinement. Novel ACME (Axial Centrifugal Metal Expeller) shearing device, based on axial compressor and rotor–stator mechanism to generate high shear rate and intense turbulence, was used to condition the melts prior to solidification. Microstructure in the Sn–Bi alloy deviated from dendritic grains with coarse eutectic pockets under conventional solidification to compact grains with well-dispersed eutectic under semisolid-state shearing. Decreasing the shearing temperature and increasing shearing time increased the globularity of grains. Following shearing, remnant liquid solidified into fine grain structure. In the immiscible Sn–Bi–Al alloy, shearing produced uniform dispersion of refined Al-rich particles in Sn-rich matrix as opposed to severe segregation under conventional solidification. The primary effect of shearing appears to originate from the thermo-solutal homogenisation of the melt and its effect on interface stability during solidification.
Keywords: Solidification, microstructure, semisolid, Sn alloys, immiscible, coarsening, grain refinement, melt shearing
Issue: 18
Start Page: 2157
End Page: 2164