(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)
摘 要: 通過透射電鏡觀察和XRD檢測(cè)分析，對(duì)比純Al試樣，研究了多向壓縮變形(MAC)過程中固溶原子及析出相對(duì)Al-4Cu合金晶粒細(xì)化效果的影響。結(jié)果表明：室溫下，經(jīng)過相同變形道次后，固溶原子的存在導(dǎo)致Al-4Cu合金所形成的亞晶粒形貌不規(guī)則，晶內(nèi)位錯(cuò)密度較高，呈長(zhǎng)約200 nm、寬約100 nm的類竹節(jié)狀，純Al中亞晶粒內(nèi)部位錯(cuò)密度低，呈直徑約600 nm的等軸狀；Al-4Cu合金在室溫下的析出相回溶過程抑制細(xì)小晶粒的形成，有利于亞晶內(nèi)部位錯(cuò)密度的降低，50 ℃下的析出相回溶及再析出過程有利于細(xì)小晶粒的形成。
關(guān)鍵字: Al-4Cu合金；強(qiáng)變形；析出相回溶；晶粒尺寸；亞晶
（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）
Abstract:The size and morphology of pure Al and Al-4Cu alloy processed by multi-axial compression (MAC) deformation were characterized by transmission electron microscopy and X-ray diffractometry to investigate the effect of solute atom and precipitated phase on grain refinement of Al-4Cu alloy by severe plastic deformation. The results show that the existence of solute atom in Al-4Cu alloy is associated with the irregular morphology of subgrain and higher dislocation density than that of pure Al. However, the former in bamboo-like shape exhibits smaller grain size with a length of about 200 nm and a width of about 100 nm than the latter in equiaxed shape with a diameter of about 600 nm. Also, at room temperature grain refinement is suppressed by the re-dissolution of severely deformed precipitated phase, which is helpful to the decrease of dislocation density, and at 50 ℃ the re-dissolution and re-precipitation of precipitate phase contributes to the grain refinement.
Key words: Al-4Cu alloy; severe plastic deformation; precipitated phase re-dissolution; grain size; subgrain
