Al-Ti-C-Sr细化剂制备的正交优化及挤压研究

Preparation of Al-Ti-C-Sr Refiner by Orthogonal Experiment and Extrusion

以工业纯铝、氟钛酸钾、石墨粉、纯锶为原料,采用原位反应法制备Al-Ti-C-Sr细化剂,通过正交实验优化Al-Ti-C-Sr细化剂的制备方案.对最优方案制备的细化剂进行挤压处理,研究了挤压态Al-3Ti-0.2C-5Sr的显微组织及其细化性能.结果表明,优化出的Al-Ti-C-Sr细化剂的方案为:成分Al-3Ti-0.2C-5Sr,氟钛酸钾和石墨粉的保温时间为60 min,纯锶的保温时间为15 min;挤压态Al-3Ti-0.2C-5Sr细化剂中的TiAl3相、Al4Sr相、Al-Ti-Sr三元相的尺寸较小,TiC粒子分布弥散.添加挤压态Al-3Ti-0.2C-5Sr细化剂之后,A356铝合金的平均晶粒尺寸由1 195μm减小到约350μm,二次枝晶臂间距由23.2μm减小到约21.5μm.

This paper prepared Al-Ti-C-Sr grain refiner by in - situ reaction with pure aluminum graphite powder, pure strontium. Orthogonal experiment was applied to optimize the composition tion process of the Al-Ti-C-Sr refiner. The prepared Al-Ti-C-Sr refiner by optimal scheme was and K2TiF6, and prepara- extruded and the microstructure and refining performance were studied. The results show the optimal scheme： composition was Al-3Ti-0. 2C-5Sr, K2TiF6 and graphite powder were held 60 min, pure strontium was held 15 min. when Al-3Ti-0. 2C-5Sr was extruded, the size of TiAl3, Al4Sr and Al-Ti-Sr phases decreases, and TiC phases distributed uniformly in the matrix. After adding extruded Al-3Ti-0.2C-5Sr in A356, the average grain size decreases from 1195 μm to 350 μm, the secondary dendrite arm spacing decreases from 23.2 μm to 21.5 μm.