【摘要】 应用自蔓延高温合成法制备出含稀土及不含稀土两种AlTiC细化剂。应用扫描电镜及X射线衍射等手段分析了中间合金及细化剂的成分、组织和形貌。结果表明:稀土对反应合成TiC微细颗粒具有重要的促进作用,添加稀土明显加快反应速度;在AlTiCRE细化剂中,由于稀土的作用,改变了TiAl3和TiC的形态和分布,减小了TiC的聚集倾向,细化了TiC颗粒尺寸,从而增加了形核基底数。AlTiCRE细化晶粒的效果优于AlTiC,而且稀土还具有明显细化枝晶组织的作用。更多还原

【Abstract】 Two type refiners, in which one contains rare earths and the other without, were prepared with self-propagating high-temperature synthesizing method. The composition, microstructure and morphologies of master alloys and refiners were investigated with scanning electron microscopy （SEM） and X-ray diffraction （XRD）. Experimental results indicate that rare earth presents obvious effect to promote the reaction synthesizing of TiC super-fine grains and accelerate reaction velocity. The existing of rare earths affects the morphologies and distributing of the TiAl₃ and TiC, restrains the congregating tendency of TiC, and refines its granularity. AlTiCRE refiner shows obvious advantages over AlTiC refiner and evident effects on refining dendvite crystal.更多还原