Next Article in Journal
Magnetic Hysteresis in Nanocomposite Films Consisting of a Ferromagnetic AuCo Alloy and Ultrafine Co Particles
Previous Article in Journal
Studies on Mathematical Models of Wet Adhesion and Lifetime Prediction of Organic Coating/Steel by Grey System Theory
Article Menu
Issue 7 (July) cover image

Export Article

Open AccessArticle
Materials 2017, 10(7), 716; https://doi.org/10.3390/ma10070716

Synthesis of Al2Ca Dispersoids by Powder Metallurgy Using a Mg–Al Alloy and CaO Particles

1
HI-LEX CORPORATION, 1-12-28 Sakaemachi, Takarazuka-City, Hyogo 665-0845, Japan
2
Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
3
Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka, Ibaragi, Osaka 567-0047, Japan
*
Author to whom correspondence should be addressed.
Received: 1 June 2017 / Revised: 21 June 2017 / Accepted: 22 June 2017 / Published: 28 June 2017
(This article belongs to the Section Structure Analysis and Characterization)
Full-Text   |   PDF [8044 KB, uploaded 29 June 2017]   |  

Abstract

The elemental mixture of Mg-6 wt %Al-1 wt %Zn-0.3 wt %Mn (AZ61B) alloy powder and CaO particles was consolidated by an equal-channel angular bulk mechanical alloying (ECABMA) process to form a composite precursor. Subsequently, the precursor was subjected to a heat treatment to synthesize fine Al2Ca particles via a solid-state reaction between the Mg–Al matrix and CaO additives. Scanning electron microscopy-energy-dispersive spectroscopy (SEM-EDS) and electron probe micro-analysis on the precursor indicated that 4.7-at % Al atoms formed a supersaturated solid solution in the α-Mg matrix. Transmission electron microscopy-EDS and X-ray diffraction analyses on the AZ61B composite precursor with 10-vol % CaO particles obtained by heat treatment confirmed that CaO additives were thermally decomposed in the Mg–Al alloy, and the solid-soluted Ca atoms diffused along the α-Mg grain boundaries. Al atoms also diffused to the grain boundaries because of attraction to the Ca atoms resulting from a strong reactivity between Al and Ca. As a result, needle-like (Mg,Al)2Ca intermetallics were formed as intermediate precipitates in the initial reaction stage during the heat treatment. Finally, the precipitates were transformed into spherical Al2Ca particles by the substitution of Al atoms for Mg atoms in (Mg,Al)2Ca after a long heat treatment. View Full-Text
Keywords: magnesium alloys; powder metallurgy; composite materials; microstructure; phase transformation; transmission electron microscopy magnesium alloys; powder metallurgy; composite materials; microstructure; phase transformation; transmission electron microscopy
Figures

Graphical abstract

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).
SciFeed

Share & Cite This Article

MDPI and ACS Style

Fujita, J.; Umeda, J.; Kondoh, K. Synthesis of Al2Ca Dispersoids by Powder Metallurgy Using a Mg–Al Alloy and CaO Particles. Materials 2017, 10, 716.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Materials EISSN 1996-1944 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top