【摘要】 为了优化中间合金细化剂的组织,进而提高细化性能,采用氟盐铝热反应法制取A l5T i1B中间合金。在化学反应热力学和动力学基础上,对中间合金典型的铸态微观组织进行了分析,并通过对比热挤压前后的微观组织,研究挤压工艺对组织的影响。结果表明,铸态条件下T iB2主要呈4种分布形态:附着在T iA l3上,分布在T iA l3之间,规则排列在晶界处,形成团聚。经热挤压之后T iA l3颗粒尺寸减小,表面趋于平滑,挤压过程中发生的再结晶现象使T iB2分布均匀弥散。要取得理想的中间合金组织,优化挤压工艺同控制化学反应和铸造凝固条件一样重要。更多还原

【Abstract】 To obtain better microstructures,Al5Ti1B master alloy was prepared by reacting complex halide salts with molten aluminum at high temperatures.The as-cast microstructures were analyzed based on the thermodynamics and flow dynamics.The effect of the extrusion process on microstructure was studied by comparing the microstructure after squeezing with the as-cast microstructure.The results show that the TiB₂ particles are attached to the TiAl₃ grains,located between the TiAl₃ grains,arranged to the α-Al grain boundaries or integrated into congregated complexes.The TiAl₃ grains become smaller and smoother during extrusion with recrystallization during the squeezing,which results in a more homogeneous distribution of the TiB₂ particles.An optimized hot extrusion process is a key factor affecting the microstructure along with the chemical reactions and the casting.更多还原