组织及耐磨性能的影响
(1. 太原理工大学 材料科学与工程学院，太原 030024；
2. 中车双喜轮胎有限公司，清徐 030400)
摘 要: 采用真空感应熔炼炉制备一种新型绿色中间合金Al-Mn-Ti-P-Cu，并添加金属Mg共同作用于过共晶Al-25Si合金，再对其进行适当热处理，最后检测实验效果，分析变质、强化、磨损机制。结果表明：该中间合金对组织中粗大的初、共晶硅及α(Al)均有明显细化作用；变质后，添加适量Mg可将Mg2Si强化相以相对细小形态引入基体，并最终在热处理后呈颗粒状均匀弥散分布基体中；随着组织的细化以及基体强度和硬度的提高，合金的磨损机制由磨粒磨损和粘着磨损的混合型磨损转化为单一的磨粒磨损，同时磨损质量损失降幅达46.6%，从而获得一种较理想的高强耐磨活塞材料。
关键字: 过共晶高硅铝合金；Al-Mn-Ti-P-Cu中间合金；Mg；变质；磨损机理
microstructure and wear resistance of hypereutectic Al-25Si alloy
（1. College of Material Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China;
2. Chonche Auto Double Happiness Tyre Co. Ltd., Qingxu 030400, China）
Abstract:The hypereutectic Al-25Si alloy was processed by a new type of green master alloy Al-Mn-Ti-P-Cu prepared in vacuum induction smelting furnace, together with some Mg. Then, the alloy was heat-treated, and different testing means were used to detect the experimental effects and its modification, strengthening and wear mechanisms were discussed. The results show that this master alloy has significant refining effects on the coarse primary Si, eutectic Si and α(Al), and adding Mg after modification can bring Mg2Si precipitate phase into the matrix, which becomes even more uniform and dispersive granules after further heat treatment. With the refinement of microstructures and enhancement of strength and hardness of the matrix, the wear mechanism is changed from both abrasive and adhesive wear to only abrasive wear, and meanwhile, its wear loss is reduced by up to 46.6%. Finally, a kind of ideal high-strength and wear-resisting piston material can be obtained.
Key words: hypereutectic high-silicon aluminum alloy; Al-Mn-Ti-P-Cu master alloy; Mg; modification; wear mechanism
