7075铝合金半固态浆料制备及其组织形成机理分析  

Preparation and Formation Mechanism Analysis of 7075 Aluminum Alloy Semi-solid Slurry

作　　者：涂琴[1] 杨兴文[2] 朱光 

机构地区：[1]国家知识产权局专利局专利审查协作河南中心,郑州450000 [2]中原工学院,郑州450007

出　　处：《中原工学院学报》2017年第4期40-45,共6页Journal of Zhongyuan University of Technology

摘　　要：采用新型半固态成形技术——蛇形通道浇注法制备7075铝合金半固态浆料。研究了浇注温度、蛇形通道材质对7075铝合金半固态浆料组织的影响,分析了7075铝合金半固态浆料的组织形成机理。研究结果表明:在其他工艺条件不变的情况下,浇注温度在660~760℃时,随浇注温度的降低,所形成的铝合金浆料组织由枝状晶向蔷薇状直至球状或类球状晶转变,浇注温度越低,其MPD值越小,NPA、ASF值越大,形成的晶粒越细小、圆整、均匀;采用纯铜质蛇形通道浇注时,所形成半固态浆料组织的MPD、NPA、ASF特征参数均优于石墨质蛇形通道;对于7075铝合金半固态浆料,重力+自搅拌+剪切+对流的混合作用使得半固态金属液的浓度场和温度场趋于均匀,晶核的择优生长取向被抑制,最终形成细小的球状或类球状晶组织。The effect of pouring temperature and serpentine channel material on the microstructure of7075 aluminum alloy semi-solid slurry was studied by using serpentine channel casting method of semi-solid forming technique to prepare 7075 aluminum alloy semi-solid slurry.And the microstructure formation mechanism of 7075 aluminum alloy semi-solid slurry was analyzed.The results show that when the pouring temperature decreases among 660-760℃ under the same process conditions,Aluminum alloy slurry structure is changed from dendrites to rosette until the spherical or spherical-like crystal transition.The lower the pouring temperature,the smaller the MPD value,the larger the NPA and ASF values,and Grain of formed is more small,round,uniform;The MPD,NPA and ASF of the semi-solid slurry are better than those of the graphite serpentine channel when the pure copper serpentine channel is used;The formation mechanism of 7075 Aluminum Alloy Semi-solid Slurry is that the concentration field and the temperature field of the semi-solid metal solution tend to be uniform due to the combination of gravity＋self-stirring＋shear＋convection,Which leaded to the preferential growth orientation of the nuclei is suppressed,and the final small spherical or globular crystal microstructure is formed.

关 键 词：7075铝合金 半固态浆料 浇注温度 蛇形通道材质 形成机理 

分 类 号：TG146.21[一般工业技术—材料科学与工程]