【摘要】：本文采用連續(xù)變斷面循環(huán)擠壓(Continuous variable cross-section recycled extrusion,CVCE)技術(shù)對(duì)擠壓態(tài)AZ31鎂合金進(jìn)行擠壓變形,研究了CVCE技術(shù)對(duì)AZ31鎂合金組織及力學(xué)性能的影響。利用光學(xué)顯微鏡、XRD等技術(shù)對(duì)AZ31鎂合金的晶粒尺寸、晶粒取向等微觀結(jié)構(gòu)進(jìn)行表征,分別沿水平方向和軸向進(jìn)行顯微硬度和室溫拉伸性能測(cè)試。并采用DOFORM有限元軟件對(duì)AZ31CVCE工藝進(jìn)行數(shù)值模擬,取得的主要研究結(jié)果有:通過(guò)數(shù)值模擬和擠壓實(shí)驗(yàn)研究確定了AZ31鎂合金CVCE擠壓最佳工藝參數(shù)。變形速度為2 mm/s、第1到3循環(huán)的擠壓溫度分別為350℃、330℃和300℃,對(duì)應(yīng)循環(huán)的保溫時(shí)間分別為13 min、11 min和10 min。隨著變形循環(huán)的增加,晶粒逐漸細(xì)化且組織均勻性改善,但隨著循環(huán)數(shù)的增加,晶粒發(fā)生異常長(zhǎng)大現(xiàn)象。晶粒取向發(fā)生了定向改變,由母材各個(gè)面都有較強(qiáng)織構(gòu)轉(zhuǎn)變?yōu)橹挥谢婵棙?gòu)較強(qiáng),而且織構(gòu)方向平行于AZ31鎂合金晶粒的c軸。在水平方向上,變形后的試樣的抗拉強(qiáng)度均得到提高,但延伸率有所降低;在軸向上,變形后抗拉強(qiáng)度和延伸率均得到了提高。采用DEFORM軟件對(duì)較優(yōu)的變形工藝參數(shù)進(jìn)行溫度場(chǎng)、應(yīng)力場(chǎng)、應(yīng)變場(chǎng)和金屬流動(dòng)方向的模擬,變形過(guò)程中發(fā)生變形能和熱能之間轉(zhuǎn)換,隨著變形循環(huán)的增加應(yīng)變量不斷累積,變形循環(huán)為5時(shí),試樣中間部位的累積應(yīng)變量可達(dá)到4,且分布較為均勻,并且模擬的應(yīng)變值與公式計(jì)算相一致。
[Abstract]:In this paper, the extrusion deformation of extruded AZ31 magnesium alloy was carried out by continuous variable section cyclic extrusion (Continuous variable cross-section recycled) technique. The effect of CVCE technology on the microstructure and mechanical properties of AZ31 magnesium alloy was studied. The grain size and orientation of AZ31 magnesium alloy were characterized by optical microscope. The microhardness and tensile properties at room temperature were measured along the horizontal and axial directions, respectively. The DOFORM finite element software is used to simulate the AZ31CVCE process. The main results are as follows: through numerical simulation and extrusion experiment, the best process parameters of CVCE extrusion for AZ31 magnesium alloy are determined. The extrusion temperature of the first to third cycles is 350 鈩，

本文編號(hào)：2181023