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采用Al--KBF4--K2ZrF6组元通过熔体直接反应法制备了ZrB2颗粒增强铝基复合材料,优化的初始合成温度范围为850～870℃,反应时间为25～30 min.扫描电镜观察结果显示:ZrB2颗粒尺寸为300～400 nm,颗粒间距200 nm左右,有团簇现象,团簇体尺寸为30～40μm.当颗粒理论体积分数为3%时,单位熔体体积内ZrB2颗粒形核数量为6.68×1017 m-3,平均线长大速率为47.3nm.s-1.分析团簇原因认为:大量细小高熔点ZrB2增加了熔体黏度,颗粒扩散阻力大,限制了颗粒迁移位移;ZrB2颗粒因密度大具有较高的沉降速率.原位反应过程分析表明:通过Al3Zr--AlB2间的分子化合及[Zr]--[B]间的原子化合得到ZrB2颗粒,是高温稳定相.
The ZrB2 particle reinforced aluminum matrix composites were prepared by melt direct reaction using Al - KBF4 - K2ZrF6 components. The optimal initial synthesis temperature ranged from 850 to 870 ℃ and the reaction time ranged from 25 to 30 min. Scanning electron microscopy The results show that the size of ZrB2 particles ranges from 300 nm to 400 nm with a cluster spacing of about 200 nm and the size of clusters ranges from 30μm to 40μm. When the theoretical volume fraction of ZrB2 particles is 3% The number of which is 6.68 × 1017 m-3 and the average growth rate of the line is 47.3nm.s-1.Analysis of the cluster reason shows that a large number of fine refractory ZrB2 increase the melt viscosity and the diffusion resistance of the particles is large, which limits the particle migration and displacement; ZrB2 particles have higher sedimentation rate due to their higher density.The in situ reaction process analysis shows that ZrB2 particles are obtained by molecular combination between Al3Zr and AlB2 and atomic combination between [Zr] and [B], which are stable phases at high temperature.