磁化学原位合成Al-Zr(CO_3)_2复合材料颗粒形貌及长大机制

Crystal Morphology and Growth Mechanism of Magnetic-chemical Reactive Synthesis Al-Zr(CO_3)_2 Reinforced Particle

利用磁化学原位反应技术成功制备了Al2O3和Al3Zr颗粒增强Al-Zr(CO3)2体系铝基复合材料。XRD、SEM和TEM分析结果表明,反应所生成的Al2O3和Al3Zr增强颗粒在基体中均匀分布;颗粒尺寸为90～120nm。内生Al3Zr的形貌主要有粒状、块状、板条状和针状。对Al-Zr(CO3)2体系,在脉冲磁场条件下,反应温度在850、900、950、1000℃时,Al3Zr形貌分别为粒状、块状、板条状和长针状或者纤维状。Al3Zr晶体表面存在生长小面facets,在晶体中观察到了清晰可见的孪晶面和孪晶形成的凹角沟槽,孪晶面为(1-1-4),孪生方向为[22-1],孪晶的存在及其数量对Al3Zr的生长形态起着重要的作用。内生Al2O3的形态主要为等轴粒状,受反应温度的影响不大。

Al_2O_3 particle and Al3Zr particle reinforced aluminum matrix composites were prepared in Al-Zr(CO3)2 system by magnetic-chemical in-situ reactive synthesis method.Crystal morphology and growth mechanism in microstructure of the composites were investigated by XRD(X-ray diffraction),SEM(scanning electron microscope)and TEM(transmission electron microscope).The results reveal that created Al_2O_3 and Al3Zr reinforcement with average size in 90～120 nm are uniformly distributed in the matrix alloy,in which in-situ Al3Zr phase exhibits particle,bulk,lamellar or acicular shape.In Al-Zr(CO3)2 system,under the condition of pulsed magnetic field,Al3Zr phase exhibits particle,bulk shape,lamellar shape and acicular shape with reaction at 850℃,900℃,950℃and 1000℃,respectively.There exists growth facets on the surface of the Al3Zr phase,and clear twin face and formed concave groove can be observed in the crystal,where twin face is(114)and twin crystal orientation is [221].The growth morphology of Al3Zr phase is closely relative to the creation and numbers of the twin crystal.In-situ equiaxed Al_2O_3 phase can be observed in the composites,which is weakly dependent on the reactive temperature.