【摘要】：對(duì)不同高徑比H/D的7A60鋁合金坯料進(jìn)行高壓扭轉(zhuǎn)實(shí)驗(yàn),借助于EBSD技術(shù)分析了變形7A60鋁合金微觀組織(晶界取向差、晶粒取向)演變規(guī)律,同時(shí)對(duì)變形7A60鋁合金進(jìn)行拉伸實(shí)驗(yàn)和斷口掃描,分析7A60鋁合金的抗拉強(qiáng)度、斷裂方式和斷裂機(jī)理。研究結(jié)果表明:高壓扭轉(zhuǎn)變形后7A60鋁合金晶粒發(fā)生了明顯破碎細(xì)化,當(dāng)高徑比H/D為0.25時(shí),晶粒取向沿001、101方向;當(dāng)進(jìn)一步減小高徑比H/D時(shí),在三叉晶界處出現(xiàn)了細(xì)小的動(dòng)態(tài)再結(jié)晶晶粒,取向角在2°≤θ≤5°范圍內(nèi)的小角度晶界比例較大,同一晶粒內(nèi)部出現(xiàn)了顏色漸變區(qū),大部分晶粒取向沿111方向;高壓扭轉(zhuǎn)變形后7A60鋁合金抗拉強(qiáng)度明顯提高,最高抗拉強(qiáng)度達(dá)到了751 MPa,提升幅度達(dá)到了20.74%,在強(qiáng)度得到大幅提高的同時(shí)伸長(zhǎng)率也得到了較好的保持,最高伸長(zhǎng)率為14%;高壓扭轉(zhuǎn)變形后7A60鋁合金斷裂方式為塑性斷裂,斷裂機(jī)理屬于微孔連接斷裂。
[Abstract]:The high pressure torsion experiment of 7A60 aluminum alloy billets with different aspect ratio H / D was carried out. The evolution law of microstructure (grain boundary orientation, grain orientation) of deformed 7A60 aluminum alloy was analyzed by means of EBSD technique. The tensile strength, fracture mode and fracture mechanism of 7A60 aluminum alloy were analyzed by tensile test and fracture scanning. The results show that the grain size of 7A60 aluminum alloy is obviously broken and refined after high pressure torsional deformation. When the aspect ratio H / D is 0. 25, the grain orientation is along the 001101 direction, and when the aspect ratio H / D is further reduced, There are fine dynamic recrystallized grains at the tripod grain boundary. The ratio of small angle grain boundary with orientation angle is larger in the range of 2 擄鈮，

本文編號(hào)：2220749