热爆法合成Al-Ti和Al-TiC晶粒细化剂及其晶粒细化效果

Preparation of Al-Ti and Al-TiC Grain Refiners by Thermal Explosion Methodand Grain Refining Effects

采用铝熔体热爆法直接合成了Al-Ti和Al-TiC两种晶粒细化剂,研究了这两种细化剂的相组成及对工业纯铝的晶粒细化效果。结果表明,合成的Al-Ti细化剂只含有第二相TiAl3相,Al-TiC细化剂只含有第二相TiC相,无其它杂相生成。TiC和TiAl3单独作为α-Al的形核相时,二者形核能力均较差,但TiC的形核、抗细化衰退能力优于TiAl3。当TiC和TiAl3共同作为α-Al的形核相时,其表现出较强的形核能力和抗晶粒细化衰退能力。这表明Al-Ti-C晶粒细化剂良好的细化效果离不开TiC和TiAl3的共同作用,适当的TiC和TiAl3组合是晶粒细化剂优良细化能力的保证。

Al-Ti and Al-TiC grain refiners were directly synthesized by self-propagating hightemperature synthesis （SHS） in aluminum liquid. The phase composition and their refining performances for commercial aluminum were studied. The results show that the SHS Al-Ti grain refiners consist of TiAl3 and α-Al, while Al-TiC grain refiner consist of TiC and α-Al. Both TiC and TiAl3 phase have poor nucleation capabilities when they are used as nucleation sites alone but TiC particle exhibits better nucleation and higher resistance to grain refining fading than TiAl3 phase. When TiC and TiAl3 are combined together to be used as the nucleation sites of α-Al, they have better nucleation ability and higher resistance to grain refining fading. It suggests that both TiC and TiAl3 contribute to the refining effect for the Al-Ti-C grain refiner, and appropriate ingredient of TiC and TiAl3 phases can refine the grains effectively.