Microstructural modification of Sn–Bi and Sn–Bi–Al immiscible alloys by shearing

Z. Cassinath, Z. Li, S. Sridhar, A. Das, H. R. Kotadia

Research output: Contribution to journalArticlepeer-review

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.

Original languageEnglish (US)
Pages (from-to)2157-2164
Number of pages8
JournalMaterials Science and Technology (United Kingdom)
Volume35
Issue number18
DOIs
StatePublished - Dec 12 2019
Externally publishedYes

Keywords

  • coarsening
  • grain refinement
  • immiscible
  • melt shearing
  • microstructure
  • semisolid
  • Sn alloys
  • Solidification

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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