浇注温度对ZA27合金枝晶形貌的影响  

Effect of Pouring Temperature on Dendrite Morphologies of ZA27 Alloy

作　　者：李向威[1] 陈体军[1] 郝远[1] 张大华[1] 刘二勇[1] 王瑞权[1] 

机构地区：[1]兰州理工大学甘肃省有色金属新材料重点实验室,甘肃兰州730050

出　　处：《铸造》2010年第7期704-707,共4页Foundry

摘　　要：通过利用扫描电镜观察断口缩松处组织形态,研究了浇注温度对ZA27合金枝晶结构的影响。结果表明:浇注温度为550℃时,初生α-Al晶粒呈细小的等轴晶;随着浇注温度的升高,细小的等轴晶逐渐变为发达的柱状或羽毛状树枝晶。浇注温度为650℃时出现羽毛状树枝晶,呈二维结构,由主干和两排晶臂组成;枝晶最初为6个生长方向,呈等轴晶结构,随着生长的进行,曲率半径小的枝晶生长受到抑制,逐渐演化为4个方向,随后在生长过程中受到邻侧枝晶及空间的影响,逐渐变为二维层片状。The effect of pouring temperature on the dendrite 3-dimension morphologies of ZA27 alloy was investigated by using of scanning electron microscope to observe morphology characteristics of dendrites that bared in porosities on fracture surfaces. The results show that the primary α-Al grains were in a fine equiaxed shape when pouring at 550 ℃. As the pouring temperature rose,the primary grains gradually evolved from the fine equiaxed grains to developed columnar dendrites or feathery dendrites. The feathery dendrite was composed of one primary arm and two rows of secondary arms and was in a 2-dimension structure when pouring at 650 ℃. The initial primary grains were also in an equiaxed form with 6 growth-directions. As they grew,the initial 6 growth-directions evolved into 4 directions due to that the dendrite arms with small curvature radius was inhibited. Finally,they became into 2-dimension lamellae under the limitations of the neighboring dendrites and the growth space.

关 键 词：浇注温度 ZA27合金 枝晶形貌 羽毛状晶 

分 类 号：TG244[金属学及工艺—铸造]