【摘要】 采用落管无容器处理技术实现了Al_46.2Fe_36.6Ti_17.2三元包共晶合金的深过冷与快速凝固,获得直径为130¹ 150μm的合金粒子,其过冷度范围为202³0 K。研究发现,在自由落体条件下,合金熔体在快速凝固过程中呈现显著的溶质截留效应,包共晶转变进行得不彻底,凝固组织中包含Fe₂Ti相、Fe Al相和τ₂相,其中Fe₂Ti相为初生相,组织呈现枝晶形貌,Fe Al相和τ₂相形成层片状包共晶组织。随着液滴直径的减小,冷却速率增加,过冷度增大,凝固组织中初生Fe₂Ti相的形貌由粗大枝晶逐渐变为细碎枝晶,一次枝晶轴长度与粒子直径呈线性减小关系;包共晶组织由长条状层片变为球状胞,并且层片间距呈指数型减小。更多还原

【Abstract】 U ndercooled Al_46.2Fe_36.6Ti_17.2quasiperitectic alloy was rapidly solidified in the form of 130¹150 μm diameter droplets inside drop tube, and the maximum undercooling of 202 K（0.14 TL） was achieved. The rapid solidification route is characterized by the primary growth of Fe₂ Ti and the following quasiperitectic transformation of L+Fe₂Ti→Fe Al+τ₂. The solidification microstructure contains Fe₂ Ti, Fe Al and τ₂phases. The primary Fe₂ Ti phase solidify into dendrite morphology,while Fe Al and τ₂phases grow into lamellar structure. As droplet diameter decreases, the primary Fe₂ Ti phase transforms from course into fine dendrites, whose average size decreases linearly. Meanwhile, the lamellar spacing of（Fe Al+τ₂）quasiperitectic structure reduces exponentially with the decrease of the droplet diameter.更多还原