高温熔体反应法制备Al-5Ti-1B细化剂

摘要

Al-5Ti-1B refiner was successfully prepared by melt reaction method .Through the thermo-dynamics calculation ,the initial reaction temperature was determined .The influence of reaction tem-perature on microstructure and absorption rate of the alloy was investigated .The phase and micro-structure of the alloy were observed by X-ray diffraction ,scanning electron microscope and energy dis-persive spectrometer .The Al-5Ti-1B refiner was extruded at high temperature to wire with the diame-ter of 9 .5mm ,and then the refinement experiment was carried out on pure aluminium .The results in-dicate that the refiner consists of TiB2 ,TiAl3 and α-Al ,and the microstructure prepared at 850℃ is the optimum and the absorption rate of Ti and B matches the best .The TiAl3 and TiB2 phases distrib-ute homogeneously in the matrix after extrusion .When adding 0 .2% (mass fraction) of Al-5Ti-1B re-finer ,the grain size of pure aluminium reduces from 3 .99mm to 0 .45mm .%利用高温熔体反应法成功制备Al-5Ti-1B细化剂.通过热力学计算,确定Al-5Ti-1B细化剂的起始反应温度,研究熔体温度对细化剂组织形貌及吸收率的影响.利用X射线衍射,扫描电子显微镜和X射线能谱仪观察细化剂的相组成和形貌,同时对Al-5Ti-1B细化剂铸锭进行高温挤压,并对挤压出的φ9.5mm丝材进行微观组织分析和细化实验.结果表明:细化剂主要由TiB2,TiAl3,α-Al相组成;850℃制备的细化剂铸锭组织形貌最佳,且Ti和B吸收率达到最佳匹配.挤压后TiAl3相呈细小的块状和TiB2弥散分布在基体内.添加0.2%(质量分数)细化剂后,纯铝的晶粒尺寸由3.99mm细化到0.45mm.