(1. 東北大學(xué) 材料與冶金學(xué)院, 沈陽(yáng) 110006;
2. 東北大學(xué) 測(cè)試中心, 沈陽(yáng) 110006)
摘 要: 探討一種連續(xù)等通道角擠壓（ECAP）新技術(shù), 實(shí)現(xiàn)了純鋁的無(wú)限長(zhǎng)度連續(xù)大變形, 制備出具有超細(xì)晶結(jié)構(gòu)的金屬材料。 組織和性能檢測(cè)表明：在連續(xù)ECAP變形一道次后, 在晶粒內(nèi)部形成了直徑為650~900 nm且內(nèi)部基本無(wú)位錯(cuò)的亞晶, 但部分大晶粒內(nèi)部仍存在高密度的位錯(cuò)網(wǎng), 材料硬度提高了87%； 經(jīng)過(guò)4道次連續(xù)ECAP變形后, 亞晶并未進(jìn)一步細(xì)化, 但亞晶界趨于平直、清晰, 且亞晶內(nèi)部基本未見位錯(cuò)組織, 材料硬度提高也不顯著； 與傳統(tǒng)ECAP相比, 連續(xù)ECAP工藝由于具有較高的變形區(qū)溫度, 促進(jìn)了晶內(nèi)位錯(cuò)的反應(yīng)即動(dòng)態(tài)回復(fù)過(guò)程, 較早形成了平直清晰的亞晶結(jié)構(gòu), 同時(shí)伴隨每道次變形過(guò)程的動(dòng)態(tài)回復(fù)也降低了最后晶格中累積的能量, 使變形兩道次后的組織和性能變化不顯著。
關(guān)鍵字: 鉛； 超細(xì)晶； 晶界； 亞晶； 連續(xù)等通道角擠壓
SONG Dan2, WEN Jing-lin1
（1. School of Materials and Metallurgy, Northeastern University,
Shenyang 110006, China;
2. Test center, Northeastern University, Shenyang 110006, China）
Abstract: A new continuous equal channel angular pressing (ECAP) technique was developed and successfully produced unlimited length of pure aluminum with ultrafine grain. After one ECAP deformation pass, profuse subgrains with the size of 650-900 nm are formed, few dislocations can be found inside the subgrains, but high density dislocation networks still are observed in some grains, the hardness of material increases 87%. After four ECAP deformation passes, the sizes of subgrains change little, but the subgrain boundary becomes straight and thinner, the increment of hardness is insignificant. Compared with the traditional ECAP technology, much higher temperature in deformed zone during the continuous ECAP deformation accelerate the process of dynamic recovery, so many clear subgrains form even after one ECAP deformation pass, the microstructures and hardness change little with the increase of ECAP deformation passes.
Key words: aluminium; ultrafine grain; grain boundary; subgrain; continuous equal channel angular pressing
