Enhanced age hardening in a Mg–2.4 at.% Zn alloy by trace additions of Ag and Ca.pdf

Scripta Materialia 57 (2007) 485–488 /locate/scriptamat Enhanced age hardening in a Mg–2.4 at.% Zn alloy by trace additions of Ag and Ca C.L. Mendis,* K. Oh-ishi and K. Hono National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan Received 15 March 2007; revised 17 May 2007; accepted 22 May 2007 Available online 27 June 2007 The effect of adding trace amounts of Ag and Ag in combination with Ca (0.1 at.% each) to a Mg–2.4 at.% Zn alloy has been found to enhance the age hardening response substantially. Transmission electron microscopy observations showed a significant refinement of the precipitate particles, while the morphology and the crystal structure of the precipitates remained the same at the peak hardness condition. 2007 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. Keywords: Precipitation; Magnesium alloys; Ageing; Trace additions Lightweight magnesium alloys have attracted signif- itates for a given volume fraction of precipitates icant interest in the last decade due to their potential available. Trace additions of ternary or quaternary ele- applications in automotive, personal electronics and ments are particularly attractive since alloying additions aerospace industries. There has been significant research are made to the bulk chemistry of the alloy and may be effort put towards the development of die and sand cast incorporated in the cast and wrought alloy systems with- magnesium alloys, while wrought magnesium alloy out