熔铸法制备高硅铝合金组织细化及性能研究

Microstructure refinement and properties study of high silicon aluminum alloy fabricated by melting-casting

采用熔铸工艺制备了Al-22 wt.%Si和Al-27 wt.%Si两种高硅铝合金。通过L9(34)正交试验研究了变质剂添加量、变质温度、保温时间和冷却速度等工艺参数对两种合金组织细化的影响。结果显示工艺参数对组织中初生硅相直径的影响程度与合金中硅含量有关,其中Al-22 wt.%Si合金受变质保温时间影响最大,而Al-27.wt%Si合金受变质剂的添加量影响最大。获得两种合金组织细化的优化工艺,可将初生硅相直径细化至20±1μm,同时合金具有高的硬度和强度,耐磨性改善。

AI-22 wt. % Si alloy and AI-27 wt. % Si silicon aluminum alloy were prepared by melting-casting. A L9 （34） orthogonal test was designed to investigate the influences of processing parameters including the modifier addition level, melting temperature, holding time and cooling rate on the microstructure refining in both alloys. The results showed that the influence extent of the parameters depended on the silicon content. The holding time was the most important factor to the diameter of primary Si in A1-22 wt. % Si, while the modifier addition level was the most important factor in A1-27 wt. % Si alloy. The optimum conditions to refine the primary Si in both alloys were obtained under which the diameter of primary Si reached 20 ± 1 μm. Meanwhile the two alloys had high hardness, strength and improved wear resistance.