摘要
In order to explore the influence of Cu element on the morphology evolution of the in-situ TiB2 particles, the10 wt.% TiB2 reinforced Al-5 wt.%Cu based composite was prepared by mixed salt casting. The morphology characterization and transformation of TiB2 reinforcements caused by Cu element were investigated by multi-scale microstructure characterization and statistics techniques. In the case of controlled casting, 5 wt.% Cu addition was found to transform the TiB2 particle morphology from hexagonal plate with sharp edges and corners to hexagonal or tetragonal prism with chamfered edges and corners with the distinguishing growth steps both on the top surface and the side surface. The TiB2 growth in Al-Cu matrix followed the rules: nano-scaled spherical nuclei-polyhedron grains-chamfered hexagonal particles-hexagonal plates-chamfered particles with obvious growth steps. The adsorption energy of Cu on different crystal surfaces of TiB2 was caculated to reveal the influence mechanism and the results indicated that Cu was preferentially adsorbed on the(10-11)TiB2 crystal planes, devoting to the small aspect ratio of TiB2.
为了探究Cu元素对原位自生TiB2颗粒形貌演变的影响,通过混合盐铸造技术制备10%(质量分数)TiB2增强Al-5%Cu(质量分数)复合材料。采用多尺度显微组织表征及统计方法研究Cu元素引起的TiB2增强相的形貌表征及演变。在控制铸造下,当添加质量分数为5%的Cu元素时,TiB2形貌颗粒由具有尖角的六方片状演变成具有倒角的六方或四方棱柱状,同时在颗粒表面和侧面均存在明显的生长台阶。TiB2颗粒在Al-Cu基体中生长遵循以下规律:纳米尺度的球形晶核-多面体晶核-具有倒棱角的六方棱柱-六方片状-具有明显生长台阶的颗粒。通过计算Cu在TiB2不同晶面上的吸附能揭示其影响机理,计算结果表明Cu优先吸附在(1011)TiB2晶面上,促使最终生成的TiB2具有较小的径厚比。
基金
Project(2017YFB110400)supported by the National Key Research and Development Program of China。
