CAJ | 학술논문

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.
침대근액상선반련속주조기술제비적6061려합금반고태배료,재불동가열온도급보온시간하진행이차가열,채용광학현미경급도상분석의고찰시양적미관형모급척촌특정,결합차열분석적방법연구가열과정중적액상형성、조직연변급정립장대과정.결과표명,이차가열온도급보온시간공동영향착미관조직연변과정,수착가열온도승고급보온시간연장,정립축점구화병장대.가열온도월고,조직연변속도월쾌;보온시간월장,정립구화병장대월명현.유효지공제이차가열온도급보온시간,능구획득균균、원정차상대세소적반고태조직.
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.