Abstract

This study investigates the fluidity change of Al-Mg binary alloys with the addition of Si and examines the factors that determine flow length in these binary and ternary alloys. Fluidity tests for Al-6Mg-xSi (all compositions in mass percent; x = 0, 3, 5, or 7) alloys were carried out using a spiral-type steel mold. The results show a decrease in both the rate of oxidation and the freezing range, as well as an increase in the heat of fusion of Al-Mg-Si ternary alloys with increasing Si content. Nevertheless, at constant superheating of 60 °C, a lower fluidity was achieved in ternary alloys of ≤ 5 pct Si content than in Al-6Mg alloy. However, further increase to 7 pct Si content yielded a flow length 25 pct higher than for Al-6Mg alloy. Further superheating above the liquidus temperature resulted in increased flow length for Al-Mg-Si ternary alloys, with a flow length increase of about 1 cm per 5 °C temperature increase. Instead of solidification range, T_α–T_e range (the temperature difference between the start of the pro-eutectic α-Al phase (T_α) and eutectic phases (T_e)), was used in this study, as it was found to be a more suitable criterion for predicting flow length for Al-Mg-Si ternary alloys. The key variables for predicting flow length were found to differ based on alloy composition. In the ternary alloys, total heat content and (T_α–T_e) range were found to be the most influential factors driving flow behavior, while the poor fluidity of Al-6Mg binary alloys was found to be driven primarily by high oxidation tendency and low latent heat of fusion.

Graphical Abstract

中文翻译：

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Si添加对Al-Mg和Al-Mg-Si熔融合金流动行为的影响

摘要

这项研究调查了添加Si的Al-Mg二元合金的流动性变化，并研究了决定这些二元和三元合金流动长度的因素。Al-6Mg- x Si的流动性测试（所有成分均以质量百分比计；x＝ 0、3、5或7）的合金是使用螺旋型钢模制成的。结果表明，随着Si含量的增加，Al-Mg-Si三元合金的氧化速率和凝固范围均降低，熔化热增加。然而，在60°C的恒定过热下，Si含量≤5 pct的三元合金的流动性低于Al-6Mg合金。然而，进一步增加到7 pct Si含量产生的流动长度比Al-6Mg合金高25 pct。在液相线温度以上进一步过热导致Al-Mg-Si三元合金的流动长度增加，每增加5°C的温度，流动长度增加约1 cm。Tα _– T _e代替凝固范围范围（亲共晶的开始之间的温度差α -Al相（Ť _α）和共晶相（Ť _ë）），在本研究中使用，因为它被认为是用于预测流动长度更合适的标准用于Al-Mg-Si三元合金。发现用于预测流动长度的关键变量因合金成分而异。在三元合金中，总热含量和（Tα _– T _e）范围是影响流动行为的最主要因素，而Al-6Mg二元合金流动性差则主要由高氧化趋势和熔化潜热低。

图形概要