Effect of Thermomechanical Processing on Grain Size, Texture and Mechanical Properties of Pure Magnesium

Abstract:

This study aims to investigate the effect of processing routes (A and Bc) and temperature on microstructure, texture and mechanical properties of pure magnesium was studied in this research. An extruded pure magnesium (~99,9 %) was subjected to severe plastic deformation (SPD) by ECAP. Deformation was conducted at 523K and 473K and two different processing routes (A and Bc) were used to control the texture. The microstructure and texture characterization of the pressed materials were carried out. It was found that the microstructure displayed a bimodal grain structure after two passes and then became homogeneous after four passes following both routes A and Bc. The misorientation distribution was examined and the results revealed that the fraction of high angle grain boundaries (HAGB) was higher at temperature 473K. The texture was randomized following route Bc whereas it became strengthened in route A after four passes. According to the Hall-Petch (HP) relationship, the yield stress of polycrystalline metals increases with a decrease in grain size. In this study, a positive slope k was achieved in the strengthened texture while a negative one was obtained in the softened texture. The ductility of ECAP processed material was considerably improved (from 23% to 38%) without sacrificing the yield stress by route Bc at 423K.

• Periodical: Materials Science Forum (Volume 985)
• Pages: 97-108
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.985.97
• Online since: April 2020
• Authors: Mouhamadou Moustapha Sarr*, Motohiro Yuasa, Hiroyuki Miyamoto
• Keywords: Magnesium, Microstructure, Processing Temperature, Texture, Yield Stress

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