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采用常规铸造和分段式倾斜板过流冷却铸造工艺制备Al-22Si-2Fe-xMn合金,研究表明:过流冷却制备工艺能够改善初生Si形貌及尺寸,但对针状富Fe相作用有限.利用扫描电镜、X射线衍射及透射电镜等手段分析过流冷却条件下Mn元素添加对富Fe相晶体结构的影响,通过摩擦磨损实验研究不同Mn/Fe质量比的过共晶Al-Si合金的硬度及耐磨损性能.结果表明:随着过流冷却铸造过共晶Al-Si合金中Mn/Fe质量比增加,合金中四方结构的长针状富Fe相逐渐减少直至基本消失,当Mn/Fe质量比为0.7时,富Fe相主要为六方结构的块状或鱼骨状α-Al_(15)(Fe,Mn)_3Si_2相,此时,合金耐磨性较未添加Mn元素时有所提升,磨损机制以磨料磨损方式为主.
Al-22Si-2Fe-xMn alloy was prepared by conventional casting and segmented inclined plate overcurrent cooling casting process. The results show that overcurrent cooling process can improve morphology and size of nascent Si, but it has limited effect on acicular Fe-rich phase The influence of Mn addition on the crystal structure of Fe-rich phase under overcurrent cooling was analyzed by means of scanning electron microscopy, X-ray diffraction and transmission electron microscopy. The friction and wear experiments were carried out to study the effect of Mn / Fe molar ratio on the structure of hypereutectic Al-Si alloy Hardness and wear resistance of the alloy.The results show that the long-needle-like Fe-rich phase in the tetragonal structure gradually decreases until almost disappeared when the mass ratio of Mn to Fe in the hypereutectic Al-Si alloy increases, When the mass ratio of Mn / Fe is 0.7, the Fe-rich phase is mainly hexagonal block or fishbone α-Al_ (15) (Fe, Mn) _3Si_2 phase. At this time, the wear resistance of the alloy is higher than that without Mn addition Has improved, the wear mechanism to abrasive wear-based.