(哈爾濱工業(yè)大學(xué) 材料科學(xué)與工程學(xué)院， 哈爾濱 150001)
摘 要: 通過(guò)半固態(tài)重熔實(shí)驗(yàn)， 并利用金相顯微鏡，對(duì)等徑道角擠壓AZ91D鎂合金的半固態(tài)組織演變進(jìn)行了研究。結(jié)果表明： 等徑道角擠壓后二次加熱等溫處理是一種適于AZ91D鎂合金的制坯方法，加熱溫度對(duì)坯料的組織有很大影響。 當(dāng)保溫時(shí)間一定時(shí)， 隨著加熱溫度的升高， 先是球化效果越來(lái)越好， 后來(lái)發(fā)生晶粒合并長(zhǎng)大現(xiàn)象， 晶粒尺寸也會(huì)逐漸長(zhǎng)大， 當(dāng)保溫時(shí)間為15min， 加熱溫度為560℃時(shí)， 二次加熱組織最好； 當(dāng)加熱溫度一定時(shí)，隨著保溫時(shí)間的延長(zhǎng)， 晶粒尺寸有長(zhǎng)大的趨勢(shì)， 當(dāng)加熱溫度為560℃，保溫時(shí)間為15min時(shí)組織球化效果最好，晶粒最細(xì)小； 當(dāng)加熱溫度和保溫時(shí)間一定時(shí)， 隨著擠壓次數(shù)的增加， 二次加熱組織的晶粒尺寸減小。
關(guān)鍵字: AZ91D鎂合金；半固態(tài)； 坯料； 二次加熱組織
（ School of Materials Science and Engineering,
Harbin Institute of Technology, Harbin 150001, China）
Abstract: By means of reheating experiments and metalloscope, microstructure evolution of AZ91D magnesium alloy extruded by an equal channel angular die is investigated in semi-solid state. The results show that reheating the AZ91D magnesium alloy extruded by an equal channel die is a kind of good method of preparing AZ91D magnesium alloy billets. The remelted temperature has strong influence on the reheating microstructure. When holding time is constant, with the increment of remelted temperature, globular effect become good firstly, then crystal grains become large. When holding time is 15min, microstructure of remelted temperature of 560℃ is the best. When the remelted temperature is constant, with the increment of holding time, the crystal grain becomes large. When remelted temperature is 560℃, microstructure of holding time of 15min is the best. When remelted temperature and holding time are constant, with the increment of number times of extrusion the crystal grain becomes small.
Key words: AZ91D magnesium alloy; semi-solid; billets; reheated microstructure
