铝熔体中原位反应生成TiB_2颗粒的机制  

ANALYSIS OF THE FORMATION MECHANISM OF TiB_2 PARTICULATE FABRICATED BY IN SITU REACTION IN MOLTEN ALUMINIUM

作　　者：杨滨[1] 王玉庆[1] 周本濂[1] 

机构地区：[1]中国科学院金属研究所

出　　处：《金属学报》1998年第1期100-106,共7页Acta Metallurgica Sinica

基　　金：国家自然科学基金!59431040;江西省自然科学基金!975018

摘　　要：借助X射线衍射（XRD）和扫描电镜（SEM）分析了铝熔体中原位反应生成TIB2颗粒的机制结果表明：（1）形成Al3Ti放出的热量是引发后续TiB2反应的原因之一；（2）在铝熔体中原位反应生成TiB2颗粒时存在扩散机制和溶解-析出机制；（3）理论计算和实验结果都表明预制块中的Al含量显著影响TiB2颗粒的生成机制,当Al的摩尔分数大于43．5％时，反应过程中TiB2颗粒按扩散机制生成，颗粒近似呈球形当Al的摩尔分数小于43．5％时，部分TiB2颗粒按溶解-析出机制生成。By making use of a technique in which TiB2 particulates are formed by an in situ reaction in molten aluminium, TiB2/Al composites have been fabricated. The formation mechanism of TiB2 particulate was studied with XRD and SEM. The results show that (1) the heat generated by the reaction 3Al1+Tis→Al3Ti is one of reasons for igniting the reactions Al3Ti+2B→ 3Al+TiB2 and Ti+2B →TiB2, (2) diffusion, solution-precipitation mechanisms occur during this process and (3) both theoretical and experimental results have shown that the effect of aluminium content in the preform on the formation mechanism of TiB2 particulate is much obvious. When the mole fraction of aluminium in the preform exceeds 43.5%, TiB2 particulates are formed by a diffusion mechanism, and the morphology of the particulates is approximately spherical. A part of TiB2 particulates is formed by a solution-precipitation mechanism when the mole fraction of aluminium is lower than 43.5%, and the TiB2 particulates have grown up to square and multilateral shape. A number of square and multilateral TiB2 particulates with growing steps have been clearly observed with SEM.

关 键 词：TIB2/AL 复合材料 原位反应 铝熔体 TIB2颗粒 

分 类 号：TB333[一般工业技术—材料科学与工程]