摘要
The microstructure and impact behavior of A356 aluminum alloy were studied after melt treatment processes of grain refinement and modification under both non-heat treated and T6 heat treated conditions. The modification and grain refinement were done with the addition of Al-10%Sr and Al-5Ti-1B master alloys, respectively. All casting parameters were kept constant in order to focus on the influence of mentioned treatments. The results indicate that the eutectic silicon morphology is the main parameter to control the impact behavior of alloy. Consequently, the individual grain refinement of as-cast alloy does not improve the impact toughness as the modification does. While, simultaneous grain refinement and modification provide higher impact toughness in comparison with individual treatments. T6 heat treatment of the alloy improves the impact toughness under all melt-treated conditions. This is related to the further modification of eutectic silicon particles. To verify the results and clarify the mechanisms, three-point bending test and fractography were used to interpret the improvement of impact toughness of the alloy.
研究A356铝合金在非热处理和T6热处理条件下经熔化处理过程中的晶粒细化和改性后的显微组织和冲击性能。通过添加Al-10%Sr和Al-5Ti-1B中间合金分别实现改性和晶粒细化。为了重点突出上述处理的影响,所有的铸造参数都保持不变。结果表明:共晶硅形貌是控制合金冲击行为的主要参数。因此,铸态合金的晶粒细化不能像改性一样改善其冲击韧性。然而,相对于单个处理,同时进行晶粒细化和改性能提供更高的冲击韧性。合金的T6热处理在所有的熔化处理条件下都改善了冲击韧性,这与共晶硅颗粒的进一步改性有关。为证明这些结果并阐明其机制,使用三点弯曲实验和金属断面的显微观察来阐述合金冲击韧性的改善。
