Effect of Hot Rolling and Equal-Channel Angular Pressing on Generation of Globular Microstructure in Semi-Solid Mg-3%Zn Alloy

Abstract:

A combination of hot rolling and equal channel angular pressing (ECAP) was explored to generate globular microstructures in the Mg-3%Zn alloy after re-heating to the semisolid state. It was found that the single-step deformation of as-cast alloy via hot rolling at 350°C with a thickness reduction of 50% refined the alloy microstructure by creating deformation bands of the Mg (α) phase with a size of the order of tenths of micrometers. After re-heating to 630 °C, the microstructure transformed into spheroidal morphologies with an average globule size of 82 μm. An additional deformation of the hot-rolled alloy by the ECAP method at 250 °C further refined the alloy microstructure to sub-micrometer grains of lath and equiaxed shapes. After re-heating of this microstructure to 630 °C the average globule size reached 62 μm, which is roughly 25% smaller than that achieved for the hot-rolled precursor. The role of strain-induced melt activation (SIMA) techniques in generation of globular morphologies in Mg-based alloys after partial re-melting is discussed.

• Periodical: Solid State Phenomena (Volumes 217-218)
• Pages: 381-388
• DOI: https://doi.org/10.4028/www.scientific.net/SSP.217-218.381
• Online since: September 2014
• Authors: Łukasz Rogal*, Frank Czerwiński, Lidia Litynska-Dobrzyńska, Piotr Bobrowski, Anna Wierzbicka-Miernik, Jan Dutkiewicz
• Keywords: ECAP, Globular Microstructure, Magnesium Alloy, Mg-Zn Alloy, Semi-Solid Metal Processing (SSM), Thixoforming

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