作　　者： ; ; ; ;

机构地区： 华南理工大学机械与汽车工程学院

出　　处： 《中国有色金属学报》 2008年第6期967-973,共7页

摘　　要： 分别在固液两相区620和630℃以及液相线以上640和650℃对半固态2024合金坯料进行等温加热,利用光学显微镜和金相图像分析系统,研究等温温度对半固态坯料部分重熔组织的影响。结果表明:坯料等温温度越高,液相形成速度越快,重熔后晶粒越细小。在液相线以上温度等温加热比在固液两相区温度等温加热时,坯料重熔后晶粒明显细小,但球化程度略低。组织演变机理分析表明,提高等温温度,液相形成速度加快导致晶粒合并受到一定的抑制是晶粒细化的主要原因,而保温时间的缩短则是晶粒球化程度降低的原因。 The semi-solid 2024 alloy billets were isothermally reheated at 620, 630, 640 and 650 ℃, respectively, The effect of isothermal temperature on the microstructure of semi-solid billet during partial remelting was studied by optical microscopy and metallographic image analysis system. The results show that the higher the isothermal temperature is, the quicker the formation rate of liquid phase is and the finer the grains are, The grains of semi-solid billet isothermally reheated over liquidus tempera^tres 640 and 650 ~C are much finer than those at solidus-liquidus zone tempera^tres 620 and 630 ~C, but the spheroidization degree is slightly lower, It is indicated that through the analysis of microstructural evolution mechanism, the restraining of grains coalescence and the shortening of holding time by accelerating the formation rate of liquid phase are the reasons of grains refinement, and the shortening of holding time is the reason of grains spheroidization degree lowering.

关 键 词： 半固态金属 部分重熔 等温温度 组织演变

领　　域： [金属学及工艺] [一般工业技术] [金属学及工艺]