Microstructure and hardness of Bi-modified magnesium AZ31 alloys subjected to severe plastic deformation
Abstract
Magnesium alloys are known as attractive materials because of their low density and good thermal conductivity. However, compared to competing metallic materials such as aluminum alloys, magnesium alloys have lower strength. Among different methods introduced for strengthening metallic materials, severe plastic deformation is notable for its efficiency and relative simplicity. This study investigates the effect of bismuth content on the microstructure evolution and hardness of magnesium AZ31 alloy subjected to severe plastic deformation through equal channel angular pressing. For this purpose, AZ31 alloys with nominal bismuth contents of 0%, 1%, and 3% were processed by up to four passes of equal channel angular pressing at 300 °C. The microstructure evolution of these alloys was then examined using optical and scanning electron microscopy. The hardness of the specimens was measured using the Vickers method. Results show that bismuth-enriched second-phase particles are fragmented during severe plastic deformation. Additionally, increasing the bismuth content leads to more rapid grain refinement during severe plastic deformation due to the pinning effect of these second-phase particles on the grain boundaries. Faster hardening rates during severe plastic deformation were observed for the bismuth-containing AZ31 alloys. This effect is attributed to the more rapid grain refinement and the increase in the Hall-Petch coefficient resulting from the presence of fine bismuth-enriched particles.
Authors retain copyright of the published papers and grant to the publisher the non-exclusive right to publish the article, to be cited as its original publisher in case of reuse, and to distribute it in all forms and media.
The Author(s) warrant that their manuscript is their original work that has not been published before; that it is not under consideration for publication elsewhere; and that its publication has been approved by all co-authors, if any, as well as tacitly or explicitly by the responsible authorities at the institution where the work was carried out. The Author(s) affirm that the article contains no unfounded or unlawful statements and does not violate the rights of others. The author(s) also affirm that they hold no conflict of interest that may affect the integrity of the Manuscript and the validity of the findings presented in it. The Corresponding author, as the signing author, warrants that he/she has full power to make this grant on behalf of the Author(s). Any software contained in the Supplemental Materials is free from viruses, contaminants or worms.The published articles will be distributed under the Creative Commons Attribution ShareAlike 4.0 International license (CC BY-SA).
Authors are permitted to deposit publisher's version (PDF) of their work in an institutional repository, subject-based repository, author's personal website (including social networking sites, such as ResearchGate, Academia.edu, etc.), and/or departmental website at any time after publication.
Upon receiving the proofs, the Author(s) agree to promptly check the proofs carefully, correct any typographical errors, and authorize the publication of the corrected proofs.
The Corresponding author agrees to inform his/her co-authors, of any of the above terms.