低频电磁场下原位合成Al-Zr-O系复合材料机制研究

为研究低频电磁场下铝基原位复合材料的合成机制,以A356-Zr(CO3)2反应组元制备出Al-Z-O系复合材料,在低频旋转电磁场条件下原位合成了微米级颗粒增强铝基复合材料.研究表明:当感应线圈内输入电流150A,频率4Hz时,对应磁场强度为0.25T,X射线衍射结果显示基体中增强相为Al3Zr和Al2O3;SEM观察该条件下合成的复合材料凝固组织发现,生成的增强颗粒细小,粒径1~2μm,而且在基体中均匀弥散分布.对原位反应的热力学和动力学过程分析表明:反应的关键环节是高温铝液和ZrO2固液相间反应,电磁场力作用加大了反应体系的混合对流运动,提高了传热传质和物质扩散速度,并促进了颗粒在基体中的弥散分布.

Mechanism of in situ fabricating composites in the system of Al-Zr-O in low frequency electromagnetic field

In order to study the mechanism of in situ fabricating aluminum matrix composites, A356-Zr(CO3)2components were used to in situ synthesize the submicron particles reinforced aluminum composites in Al-Zr-O system in low frequency rotating electromagnetic field. When the input current and frequency were 150 A and 4 Hz respectively in inductive coils, the corresponding magnetic intensity was 0.25 T. The XRD result showed that the reinforced phases were Al3Zr and Al2O3.The SEM observation demonstrated that the sizes of reinforced particles were about 1～2 μm.The particles were well distributed in the matrix. Thermodynamic and kinetic process analysis showed that the key step was the solid-liquid reaction between molten aluminum and zirconium dioxide. Electromagnetic force accelerated the complex convection, enhanced the heat, mass transfer and diffusion process, and improved the distribution status of particles in matrix.