半固态2024合金部分重熔新工艺与组织演变  

Novel Partial Remelting Process and Microstructure Evolution of Semi-Solid 2024 Alloy

作　　者：王顺成[1] 李元元[1] 陈维平[1] 郑小平[1] 

机构地区：[1]华南理工大学,广东广州510640

出　　处：《稀有金属材料与工程》2009年第A01期192-196,共5页Rare Metal Materials and Engineering

基　　金：中国博士后科学基金资助项目(20060400749);华南理工大学博士后创新科学基金资助项目

摘　　要：提出半固态坯料先在液相线以上某温度适当等温加热,然后再降低温度至两相区继续等温保温的两步法部分重熔新工艺。采用该工艺对低过热度浇注半固态2024合金坯料进行部分重熔试验,利用光学显微镜和金相图像分析系统,研究了坯料组织演变规律,并与两相区等温部分重熔工艺进行了比较。结果表明,采用两步法部分重熔工艺,由于坯料升温速度加快和熔化过热温度提高,抑制了晶间共晶相的溶解扩散,晶间液相形成速度明显加快,对晶粒合并长大具有一定的抑制作用,并加速晶粒球化,坯料部分重熔后,晶粒更加细小和圆整。A two-step partial remelting process was proposed and applied to perform partial remelting experiments on the semi-solid 2024 alloy billet prepared by low superheat pouring. In this process, the semi-solid billet was firstly heated isothermally over liquids temperature for a few seconds, and then held isothermally at solidus-liquidus zone temperature. The microstructure evolution of the semi-solid billet during the two-step partial remelting process was studied and compared with that during isothermal partial remelting process. The results show that the formation rate of liquid phase of the semi-solid billet during the two-step partial remelting process is faster than that during the isothermal partial remelting process. The accelerating of liquid phase formation during the two-step partial remelting process can restrain the coalescence of grains to a certain extent, and thus reduce the growth rate of grains and promote the spheroidization rate. The grains of the semi-solid billet partially remelted by the two-step partial remelting process are finer and rounder than those by the isothermal partial remelting process.

关 键 词：半固态金属 触变成形 部分重熔 组织演变 

分 类 号：TG249[金属学及工艺—铸造]