Metallurgical Abstracts on Light Metals and Alloys vol.54
Coherency Evaluation of α-Mg/C15–Al2Ca Interface for a Mg–Al–Ca Alloy
Hiromu Hisazawa*, Sakiko Kashiwase** and Yoshihiro Terada**
*Graduate School of Technology, Industrial and Social Sciences, Tokushima University
**Department of Materials Science and Engineering, Tokyo Institute of Technology
[Published in Journal of the Japan Institute of Light Metals, Vol. 71 (2021), pp. 127–129]
https://www.jstage.jst.go.jp/article/jilm/71/2/71_710203/_article/-char/en
E-mail: terada.y.ab[at]m.titech.ac.jp
Keywords: magnesium alloy, C15–Al2Ca, aging, HRTEM, coherency
The C15–Al2Ca precipitates were observed using HRTEM to identify the coherency of the α-Mg/C15–Al2Ca interface for the Mg–5Al–1.5Ca alloy aged at the temperature range from 548 to 598 K. The α/C15 coherent interface turned to the semi-coherent one by the introduction of misfit dislocations on the planar surface of the C15 precipitates for the alloy aged at 598 K for 1 h, whereas the coherency was maintained for the alloy aged at 548 K for 10 h. The curve showing the loss of interface coherency was drawn in the TTP diagram for the Mg–5Al–1.5Ca alloy, which is indicative that the α/C15 interface coherency is remained within 3.6 × 107 s (10000 h) at 500 K.
Figure HRTEM images of the C15–Al2Ca precipitate observed in the Mg–5Al–1.5Ca alloy aged at 548 K/10 h (a) and 598 K/1 h (b), taken with B = [11-20]α. The spots with dark contrast on the planar surface of the precipitate are indicated with arrowheads in (b).