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采用落管无容器处理技术实现了Al_(46.2)Fe_(36.6)Ti_(17.2)三元包共晶合金的深过冷与快速凝固,获得直径为130~1 150μm的合金粒子,其过冷度范围为202~30 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Fe_2Ti相、Fe Al相和τ_2相,其中Fe_2Ti相为初生相,组织呈现枝晶形貌,Fe Al相和τ_2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Fe_2Ti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。
The deep overcooling and rapid solidification of the Al_ (46.2) Fe_ (36.6) Ti_ (17.2) ternary eutectic alloy were achieved by using the tubeless vessel processing technology to obtain the alloy particles with the diameter of 130-1 150μm. The supercooling degree The range is from 202 to 30 K. The results show that under free fall condition, the alloy melt shows a significant solute retention effect during rapid solidification, and the eutectic transformation is not complete. The solidified microstructure contains Fe 2 Ti phase, Fe Al phase and τ 2 phase. The Fe 2 Ti phase As the primary phase, the dendritic structure was presented in the microstructure, and the Fe Al phase and the τ_2 phase formed a sheet-like eutectic structure. As the droplet diameter decreases, the cooling rate increases and the supercooling degree increases. The morphology of the primary Fe_2Ti phase in the solidified microstructure gradually changes from coarse dendrites to finely dendritic crystals. The length of primary dendrite axis decreases linearly with particle diameter Small relationship; package eutectic into spherical cells by the long strip, and layer spacing decreased exponentially.