(華南理工大學(xué) 機(jī)械與汽車工程學(xué)院 國(guó)家金屬材料近凈成形工程技術(shù)研究中心，廣州 510640)
摘 要: 采用田口方法分析擠壓鑄造參數(shù)對(duì)Al5Cu0.4Mn合金中Cu宏觀偏析的影響規(guī)律，并預(yù)測(cè)在優(yōu)化的擠壓鑄造參數(shù)條件下Cu的偏析程度。結(jié)果表明：擠壓鑄造參數(shù)對(duì)Cu宏觀偏析影響由大到小依次為澆注溫度、模具溫度、擠壓力和擠壓前延遲時(shí)間；在680 ℃澆注溫度、200 ℃模具溫度和75MPa擠壓力下，能得到宏觀偏析較小的鑄件。經(jīng)掃描電鏡和金相分析：擠壓鑄造易造成Cu的正偏析，主要因?yàn)楣桃航缑媲把靥幐汇~液相在壓力的強(qiáng)制補(bǔ)縮下，通過枝晶骨架通道被擠向鑄件心部，而并非重力鑄造下的逆偏析現(xiàn)象；且在擠壓鑄件內(nèi)形成平行于模壁的長(zhǎng)條魚骨狀共晶偏析帶，這種偏析帶從鑄件表面往心部逐漸減少。
關(guān)鍵字: Al-Cu合金；擠壓鑄造；田口方法；宏觀偏析
（National Engineering Research Center of Near-Net-Shape Forming for Metallic Materials, School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640, China）
Abstract:Taguchi method was used to investigate the effects of applied pressure(p), pouring temperature(Tp), die temperature(Td) and delay time(td) on the macrosegregation of Cu in the squeeze casting of Al5Cu0.4Mn alloy. And the level of macrosegregation in cast ingot under optimized conditions was predicted successfully. The results show that the influence sequence of squeeze casting parameters on macrosegregation from large to small is Tp, Td, p, td. The pouring temperature of 680 ℃, die temperature of 200 ℃ and applied pressure of 75 MPa were proposed for obtaining the sound squeeze castings. Through analysis of composition and microstructure by SEM and OM, it is revealed that the squeeze casting leads to the normal segregation of Cu rather than inverse solute concentration profiles under gravity casting conditions. It is the action of applied pressure that resulted the filling of shrinkage porosity with backflow of solute-rich liquid along the interdendritic channels. And fish-bone-like segregation strips form, which are parallel to the die wall. The amount of segregation strips decreases from edge to center in the cast ingot.
Key words: Al-Cu alloy; squeeze casting; Taguchi method; macrosegregation
