Abstract

Minor Zr and V were added individually and jointly to Al–12.5Si–1Cu alloy to develop heat-resistant aluminum alloys. The as-cast microstructure, room temperature, and high temperature (350 °C) tensile properties and the strengthening mechanism of the modified alloys were investigated. The results show that the rod-like (Al, Si)₃Zr and hexagonal (Si, Al)₂V precipitates are respectively found in the alloys with individually added Zr or V. At the same time, they were transformed into (Al, Si)₃(Zr, V) and (Si, Al)₂(V, Zr) when Zr and V were added together. Individually added Zr or V could change the eutectic silicon aspect ratio, but the largest effect was recorded for the combined addition 0.3 wt% Zr + 0.4 wt% V. The addition of Zr and V had no significant impact on the room temperature tensile strength of the alloys but improved the yield strength. Individual additions of Zr and V caused negligible improvements in high-temperature tensile strength of alloys tested. In contrast, the combined Zr + V additions resulted in the substantial improvement with tensile strength at 350 °C reaching 79.4 MPa, i.e. 89% higher than the base alloy. The analysis shows that the increase of eutectic silicon aspect ratio and the solution strengthening of trace V in eutectic silicon is the leading cause of improving high-temperature tensile strength. The brittle, blocky primary silicon, coarse rod-like (Al, Si)₃(Zr, V), and hexagonal (Si, Al)₂(V, Zr) precipitates are detrimental to high-temperature properties.

Graphic Abstract

中文翻译：

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Zr和V改性的铸造共晶Al-Si-Cu合金的组织和拉伸性能

摘要

将次要Zr和V单独或共同添加到Al–12.5Si–1Cu合金中以开发耐热铝合金。研究了改性合金的铸态组织，室温和高温（350°C）拉伸性能以及强化机理。结果表明，在单独添加Zr或V的合金中分别发现了棒状（Al，Si）₃ Zr和六角形（Si，Al）₂ V沉淀物。同时，它们被转化为（Al， Si）₃（Zr，V）和（Si，Al）₂Zr和V加在一起时的（V，Zr）。单独添加Zr或V可以改变共晶硅的长径比，但是记录下0.3wt％Zr + 0.4 wt％V的合并添加效果最大。Zr和V的添加对室温拉伸强度没有明显影响。合金，但提高了屈服强度。Zr和V的单独添加对所测试合金的高温拉伸强度的影响可忽略不计。相反，Zr + V的组合添加带来了显着改善，在350°C时的拉伸强度达到79.4 MPa，即比基础合金高89％。分析表明，共晶硅纵横比的增加和痕量V在共晶硅中的固溶强化是提高高温抗拉强度的主要原因。脆弱的₃（Zr，V）和六角形（Si，Al）₂（V，Zr）析出物不利于高温性能。

图形摘要