(中南大學(xué) 材料科學(xué)與工程學(xué)院，長(zhǎng)沙 410083)
摘 要: 采用硬度、腐蝕速率、剝落腐蝕、慢應(yīng)變速率拉伸測(cè)試及透射電鏡和差示掃描量熱法研究預(yù)拉伸后時(shí)效制度對(duì)7050鋁合金板材顯微組織、硬度和抗腐蝕性能的影響。結(jié)果表明：峰時(shí)效合金硬度最大，抗腐蝕性能最差；過(guò)時(shí)效和回歸再時(shí)效與峰時(shí)效相比，合金的硬度值減小，抗腐蝕性能變好；在高溫+峰時(shí)效中的高溫時(shí)效階段，GP區(qū)發(fā)生回溶，有利于η′和η相的直接形核析出，晶內(nèi)析出相長(zhǎng)大、不均勻分布，合金硬度減小；晶界析出相粗化、斷續(xù)分布，合金抗腐蝕性能提高。
關(guān)鍵字: 7050鋁合金；預(yù)拉伸；時(shí)效；腐蝕性能
（School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:The effects of aging after pre-stretching process on microstructure, hardness, and corrosion resistance of the 7050 aluminum alloy plate were investigated by means of hardness tests, corrosion rate tests, exfoliation corrosion tests, slow strain rate tensile(SSRT) tests, transmission electron microscopy and differential scanning calorimetry(DSC). The results indicate that the peak-aged 7050 aluminum alloy possesses the highest hardness, but its corrosion resistance is poor. The overaging and the retrogression and re-aging treatments lower the hardness, but improve the corrosion resistance of the 7050 aluminum alloy compared with the peak-aging treatment. At the high temperature aging stage of the high temperature and a subsequent low temperature aging, GP zone can be reversed, which is beneficial to the nucleation of η′ and η phases. Consequently, the precipitates within grains become coarser and distribute uniformly, leading to the decrease of hardness. Meanwhile, the precipitates at grain boundaries become coarser and discontinuous resulting in an improved corrosion resistance.
Key words: 7050 aluminum alloy; pre-stretching; aging; corrosion resistance
