SIMA法制备半固态材料过程中球状晶粒粗化机制的研究  

Mechanism of Spherical Grain Coarsening in Preparation of Semi-solid Materials by SIMA Method

作　　者：曹苗 赵娟娟 张琦[1] CAO Miao;ZHAO Juan-juan;ZHANG Qi(School of Mechanical Engineering,Xi'an Jiaotong University,Xi'an 710049,China;State Key Laboratory of Material Processing and Die&Mould Technology,Huazhong University of Science and Technology,Wuhan 430074,China)

机构地区：[1]西安交通大学机械工程学院,西安710049 [2]华中科技大学,材料成形与模具技术国家重点实验室,武汉430074

出　　处：《精密成形工程》2020年第6期37-43,共7页Journal of Netshape Forming Engineering

基　　金：陕西省自然科学基金青年基金(2019JQ-598);材料成形与模具技术国家重点实验室开放课题研究基金(P2020-014)。

摘　　要：目的提高半固态金属坯料的制备效率。方法针对6061变形铝合金,提出了一种高效率的旋转锻造应变诱发法制备半固态材料的新工艺。通过比较不同半固态等温热处理条件下的微观组织,分析了等温热处理过程中旋转锻造材料微观组织的演变过程和粗化机制,获得了制备半固态6061铝合金材料的合理工艺参数。结果当旋锻应变量为0.44时,在620~630℃保温5 min,晶粒尺寸为48.1~52.8μm,晶粒形状系数为0.8~0.82;保温温度为620,630,640℃下球状晶粒长大速率分别为407.45,841.43,1038.03μm^3/s。结论球状晶粒的平均晶粒尺寸随着保温时间增加和保温温度的升高而增大,球状晶粒的长大主要受到晶粒的合并长大和Ostwald熟化两种机制的共同作用,并且随着保温时间的增加,Ostwald熟化逐渐起主导作用;并且球状晶粒的粗化速率随着温度的升高而增加。The work aims to improve the production efficiency of semi-solid metallic alloys.A rotary swaging strain induced melt activation method with high efficiency was proposed to prepare the semi-solid 6061 wrought aluminium alloy.The microstructural evolution and coarsening mechanism of the spherical grain during the isothermal heat treatment process were studied by comparison experiments at the different temperatures.The reasonable technological parameters for preparation of semi-solid 6061 aluminum alloy were obtained.When the strain of rotary swage was 0.44,the rotary swaged billets heated at 620-630℃holding for 5 min,and the grain size was 48.1-52.8μm,and shape factor of grain was 0.8-0.82.And the grain growth rate were 407.45,841.43,1038.03μm^3/s at the holding temperature of 620,630,640℃,respectively.These results show that the average grain size of spherical grain increases with the holding time increasing and holding temperature rising.The growth of spherical grains is mainly effected by the combination of grains'merger growth and Ostwald ripening,and Ostwald ripening gradually plays a leading role with the extension of holding time.Also the grain coarsening rate increases with the temperature rising.

关 键 词：6061铝合金 半固态 粗化机制 微观组织 

分 类 号：TG249.9[金属学及工艺—铸造]