6061铝合金半固态坯料二次加热工艺及组织演变  

Reheating Process and Microstructural Evolution of Semi-solid 6061 Aluminum Alloy

作　　者：尚淑珍[1] 路贵民[2] 赵祖欣[1] 

机构地区：[1]华东理工大学机械与动力工程学院 [2]华东理工大学资源与环境工程学院

出　　处：《特种铸造及有色合金》2010年第2期99-102,共4页Special Casting & Nonferrous Alloys

基　　金：国家自然科学基金资助项目(50874049)

摘　　要：针对近液相线半连续铸造技术制备的6061铝合金半固态坯料,在不同加热温度及保温时间下进行二次加热,采用光学显微镜及图像分析仪考察试样的微观形貌及尺寸特征,结合差热分析的方法研究加热过程中的液相形成、组织演变及晶粒长大过程。结果表明,二次加热温度及保温时间共同影响着微观组织演变过程,随着加热温度升高及保温时间延长,晶粒逐渐球化并长大。加热温度越高,组织演变速度越快;保温时间越长,晶粒球化并长大越明显。有效地控制二次加热温度及保温时间,能够获得均匀、圆整且相对细小的半固态组织。Microstructure and size of 6061 aluminum alloy semi-solid billets prepared by near-liquidus semi-continuous casting, which was reheated at different heating temperature and holding time, were observed by the Nikon E600POL optical microscope and image analyzer to investigate the formation of liquid phase, microstructure evolution and grain growth during reheating process combining with differential thermal analysis (DTA). The results reveal that microstructural evolution is controlled by reheating temperature and holding time. With increasing in heating temperature and extending in holding time, grain is grown spherically and gradually, furthermore, microstructural evolution is faster and faster with increasing in heating temperature, and grain is grown more and more spherically with extending in holding time. The 6061 aluminum alloy semi-solid billets with homogeneous and round as well as fine structure can be prepared by effectively controlling reheating temperature and holding time.

关 键 词：半固态 6061铝合金 二次加热 组织演变 相变 

分 类 号：TG27[金属学及工艺—铸造]