原位生成Mg_2Si/AM60复合材料的热力学与动力学分析

Thermodynamics and Kinetics of In-situ Synthesized Mg_2Si/AM60 Composites

以Si作为反应添加物,原位生成了Mg2Si增强镁基复合材料。借助光学显微镜(OM)及X射线衍射分析(XRD),发现复合材料组织由初生α-Mg、β-Mg17Al12相以及增强相Mg2Si组成。从热力学和动力学两方面,探讨了原位生成Mg2Si的机制,建立了体系原位生成Mg2Si的动力学模型。结果表明,影响反应速度的主要因素为体系温度、Si颗粒大小以及扩散中间层的厚度。

The Mg2Si particulate reinforced Mg matrix composites was prepared by in-situ synthesized method with Si as reactive agent.The microstructure of the composites was observed by OM(optical microscope),XRD(X-ray diffractionmeter).It is found that microstructure of the composites is composed of α-Mg phase,β-Mg17Al12 phase and Mg2Si reinforcement.The mechanism of in-situ synthesized Mg2Si phase was expounded based on thermodynamics and kinetics,and the kinetic model was established.The results show that the reactive rate of in-situ synthesis is controlled by system temperature,Si particle size and the thickness of diffusion layer.