超重力熔铸铁基金属陶瓷材料多相运动学特征及其致密化机制

Multiphase Kinematics Characteristics and Densification Mechanism of Iron-based Metalloceramics Functionally Gradient Materials via Combustion Synthesis Infiltration under an Ultra-gravity Field

摘要:

采用Fe₃O₄/Al/铁基硬质合金的铝热体系,超重力熔铸铁基金属陶瓷梯度材料,分析了超重力场中硬质合金颗粒在高热高温铁熔体内的运动特征及其致密化机制,研究结果表明,根据Stocks定律,弥散相在高温熔体内的运动速度影响因素主要有颗粒与基体熔体密度差、超重力系数、颗粒半径及温度等,在一定的超重力系数下,材料的致密度与气泡尺寸、铁熔体存在时间有关。V-Fe和Cr-Fe两种颗粒主要集中于金属陶瓷材料的顶端,沿超重力方向粒子尺寸逐渐减小,而Mo-Fe颗粒主要集中在金属陶瓷材料与45钢分界面处,不同颗粒在材料内的分布状况有较大差异,这是金属陶瓷材料硬度呈梯度变化的主要原因。

Abstract:

Iron-based metalloceramics functionally gradient material (FGM) was prepared by combustion synthesis casting under an ultra-gravity field through using thermite system with Fe₃O₄/Al/Fe-based Cemented Carbide. Multiphase kinematics characteristics and densification mechanism of cemented carbide particles in ultra-gravity field were explored. The research results indicated that based on the Stocks rules, effect of translational speed of particles in high-temperature melts will be determined by density variation between the particles and melt, ultra-gravity coefficient, radius of particles, temperature and so on. Under certain ultra-gravity coefficient condition, material density was related to bubble size, existence time of iron melt. On the top of the material, there are mainly gathered two kinds of particles with ferrovanadium and ferrochrome, whose size will decrease follow the direction of ultra-gravity field. However, ferromolybdenum mainly gathered in the interface between FGM and 45 steel. The mostSofSdiscrepancies of distribution characteristics for different particles were exhibited because of their difference of density and melting point. The aspect leads to the gradient variation of hardness distribution for the FGM.