(1. 中南大學(xué) 材料科學(xué)與工程學(xué)院，長(zhǎng)沙 410083；
2. 中南大學(xué) 有色金屬材料科學(xué)與工程教育部重點(diǎn)實(shí)驗(yàn)室，長(zhǎng)沙 410083；
3. 長(zhǎng)沙新振升集團(tuán)有限公司，長(zhǎng)沙 410100)
摘 要: 采用熱模擬研究一種新型Al- Mg-Si-Cu合金的熱變形行為，制定該合金的低溫快速擠壓工藝和在線(xiàn)熱處理制度，利用電子萬(wàn)能實(shí)驗(yàn)機(jī)、光學(xué)顯微鏡、掃描電鏡對(duì)合金的力學(xué)性能和組織進(jìn)行分析。結(jié)果表明：新型Al- Mg-Si-Cu合金為正應(yīng)變速率敏感材料；該合金的熱壓縮變形流變應(yīng)力行為可用雙曲正弦形式的本構(gòu)方程來(lái)描述，也可用Zener-Hollomon參數(shù)來(lái)描述，其變形激活能為189.82 kJ/mol；隨著熱變形溫度的升高和應(yīng)變速率的減小，合金的主要軟化機(jī)制逐步由動(dòng)態(tài)回復(fù)轉(zhuǎn)變?yōu)閯?dòng)態(tài)再結(jié)晶；合金低溫快速擠壓后，經(jīng)過(guò)在線(xiàn)風(fēng)淬停留3 h，然后200 ℃人工時(shí)效3 h，其抗拉強(qiáng)度達(dá)到305 MPa，屈服強(qiáng)度達(dá)到265 MPa。
關(guān)鍵字: Al-Mg-Si-Cu合金；熱變形；流變應(yīng)力；顯微組織；力學(xué)性能
novel Al-Mg-Si-Cu alloy
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education,
Central South University, Changsha 410083, China;
3. Changsha New Zhensheng Group Co., Ltd, Changsha 410100, China）
Abstract:The hot deformation of a novel Al-Mg-Si-Cu alloy was studied by thermal simulation. High-speed extrusion process at low temperature and on-line heat treatment were developed. Mechanical properties and microstructures were analyzed by universal testing machine, optical microscopy and scanning electron microscopy. The results show that the novel Al-Mg-Si-Cu alloy is sensitive to strain rate. The hot deformation behavior of this alloy can be described by a constitutive equation in hyperbolic sine function, and can also be described by a Zener-Hollomon parameter with a hot deformation activation energy of 189.82 kJ/mol. The softening mechanism transforms from dynamic recovery to dynamic recrystallization with increasing temperature and decreasing strain rate. After high-speed extrusion at low temperatures, on-line air quenching for 3 h, and artificial aging at 200 ℃ for 3 h, the tensile strength of the alloy reaches 305 MPa, with the yield strength of 265 MPa.
Key words: Al-Mg-Si-Cu alloy; hot deformation; flow stress; microstructure; mechanical properties
