Al-18%Si-5%Fe合金組織和性能的影響
(東北大學(xué) 材料與冶金學(xué)院，沈陽 110004)
摘 要: 提出了波浪形傾斜板流變鑄造(WSP)裝置制備過共晶Al-Si-Fe合金的方法，對Al-18％Si-5％Fe合金流變鑄造與球化處理進(jìn)行研究。結(jié)果表明，WSP流變鑄造可以明顯改善合金中初晶硅、Al18Si10Fe5和Al8Si2Fe相的形貌。隨著澆注溫度降低，各相趨于細(xì)化和球化。WSP流變鑄造過程中合金組織的形成源于3種機(jī)制：結(jié)晶雨帶來的晶核增殖，斜板強(qiáng)冷卻作用下晶體抑制生長和流動剪切作用下晶體破碎。WSP流變鑄造與球化處理進(jìn)一步改善Al-18%Si-5%Fe合金組織，合金維氏硬度達(dá)到87.5。在干摩擦條件下Al-18%Si-5%Fe合金的磨損率達(dá)到5.4 mg/h。
關(guān)鍵字: 過共晶Al-Si合金；波浪形傾斜板；流變鑄造；球化
（School of Materials and Metallurgy, Northeastern University, Shenyang 110004, China）
Abstract:A novel method of preparing hypereutectic Al-Si-Fe alloy was proposed by wavelike sloping plate (WSP) rheocasting device, and the rheocasting and spheroidisation treatment of Al-18%Si-5%Fe alloy were investigated. The results reveal that the morphologies of primary crystal Si, Al18Si10Fe5 and Al8Si2Fe phase in this alloy can be improved obviously by WSP rheocasting. With the decrease of pouring temperature, various phases tend to be refined and spheroidised. The formation of microstructures in this alloy originates from three mechanisms such as crystal nucleus multiplication brought by crystallization rain, crystal restraining growth under strong cooling of sloping plate and crystal break-up under flow shear. The WSP rheocasting and spheroidisation treatment further improve the microstructure of Al-18%Si-5%Fe alloy. The Vickers hardness of the alloy is 87.5. The wear rate of Al-18%Si-5%Fe alloy under dry friction is 5.4 mg/h.
Key words: hypereutectic Al-Si alloy; wavelike sloping plate; rheocasting; spheroidisation
