Effect of scandium on the phase composition and hardening of casting aluminum alloys of the Al–Ca–Si system

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• 作者：N. A. Belov ; E. A. Naumova ; V. V. Doroshenko…
• 关键词：Al–Ca–Si–Sc system ; scandium ; EPMA ; phase composition ; calcium ; eutectic ; Al3Sc nanoparticles ; hardening
• 刊名：Russian Journal of Non-Ferrous Metals
• 出版年：2016
• 出版时间：November 2016
• 年：2016
• 卷：57
• 期：7
• 页码：695-702
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Metallic Materials;
• 出版者：Allerton Press
• ISSN：1934-970X
• 卷排序：57

文摘

The phase composition of the Al–Ca–Si–Sc system is investigated in aluminum corner uisng computational (Thermo-Calc) and experimental (optical microscopy, scanning electron microscopy, and electron probe microanalysis) methods. The influence of annealing on the structure and hardness of alloys containing 0.3 wt % Sc is investigated in the region up to 550°C. It is shown that the maximum in the hardening curve caused by the isolation of nanoparticles of the Al₃Sc (L1₂) is attained after annealing at temperatures of 300–350°C in alloys belonging to the phase region (Al) + Al₄Ca + Al₂Si₂Ca ((Al) is the aluminum-based solid solution). Scandium completely enters the (Al) composition in alloys of this region, while the silicon concentration is minimal in it. On the other hand, hardening is almost absent in alloys from the (Al) + (Si) + Al₂Si₂Ca phase region. The possibility in principle to form the casting alloys based on the (Al) + Al₄Ca + Al₂Si₂Ca eutectic hardened without quenching is substantiated.