(1. 中南大學(xué) 材料科學(xué)與工程學(xué)院，長(zhǎng)沙 410083；
2. 中國(guó)商用飛機(jī)有限責(zé)任公司 上海飛機(jī)設(shè)計(jì)研究院，上海 200232)
摘 要: 采用差熱分析、X射線衍射分析、光學(xué)顯微鏡、掃描電鏡、透射電鏡和常溫拉伸等方法研究分級(jí)均勻化工藝對(duì)7055鋁合金顯微組織、枝晶偏析、Al3Zr粒子析出行為和力學(xué)性能的影響。結(jié)果表明：合金經(jīng)(468 ℃、24 h)+(473 ℃、4 h)的分級(jí)均勻化處理后，消除了鑄錠晶界上的非平衡凝固共晶組織；鑄錠先于264 ℃保溫最有利于獲得尺寸細(xì)小、均勻彌散分布的Al3Zr粒子；在單級(jí)均勻化基礎(chǔ)上增加473 ℃的短時(shí)高溫均勻化，能夠提高合金基體中溶質(zhì)原子的固溶度，增強(qiáng)時(shí)效強(qiáng)化效果，提高綜合性能。
關(guān)鍵字: 7055鋁合金；均勻化；Al3Zr粒子；顯微組織；力學(xué)性能
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Shanghai Aircraft Design and Research Institute, Commercial Aircraft Corporation of China, Shanghai 200232, China）
Abstract:The effects of step-homogenization on the microstructures, dendritic segregation, precipitation of Al3Zr particles and ultimate mechanical properties of aluminum alloy 7055 were studied by differential scanning calorimetry, X-ray diffractometry, optical microscopy, scanning electron microscopy, transmission electron microscopy and tensile test. The result show that the step-homogenization treatment, which comprises of the isothermal heating of the ingots at 468 ℃ for 24 h, then heating to 473 ℃ for 4 h, greatly eliminates the nonequilibrium solidified eutectic which exists on the grain boundaries. The previous heating at 264 ℃ is most favorable for the precipitation of fine and uniformly distributed Al3Zr particles. The additional short-term and high temperature heating at 473 ℃ on the basis of single-stage homogenization maximizes the solution ability of solid solute in the matrix, enhances the ageing strengthening effect and improves the comprehensive properties of the alloy.
Key words: 7055 aluminum alloy; homogenization; Al3Zr particles; microstructure; mechanical properties
