組織及耐磨性能的影響
(1. 太原理工大學(xué) 材料科學(xué)與工程學(xué)院，太原 030024；
2. 中車(chē)雙喜輪胎有限公司，清徐 030400)
摘 要: 采用真空感應(yīng)熔煉爐制備一種新型綠色中間合金Al-Mn-Ti-P-Cu，并添加金屬M(fèi)g共同作用于過(guò)共晶Al-25Si合金，再對(duì)其進(jìn)行適當(dāng)熱處理，最后檢測(cè)實(shí)驗(yàn)效果，分析變質(zhì)、強(qiáng)化、磨損機(jī)制。結(jié)果表明：該中間合金對(duì)組織中粗大的初、共晶硅及α(Al)均有明顯細(xì)化作用；變質(zhì)后，添加適量Mg可將Mg2Si強(qiáng)化相以相對(duì)細(xì)小形態(tài)引入基體，并最終在熱處理后呈顆粒狀均勻彌散分布基體中；隨著組織的細(xì)化以及基體強(qiáng)度和硬度的提高，合金的磨損機(jī)制由磨粒磨損和粘著磨損的混合型磨損轉(zhuǎn)化為單一的磨粒磨損，同時(shí)磨損質(zhì)量損失降幅達(dá)46.6%，從而獲得一種較理想的高強(qiáng)耐磨活塞材料。
關(guān)鍵字: 過(guò)共晶高硅鋁合金；Al-Mn-Ti-P-Cu中間合金；Mg；變質(zhì)；磨損機(jī)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
