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金属异质界面对微波烧结扩散影响的在线实验和相场模拟联合分析
Analysis on the Effect of Hetero Interface between Metal during Microwave Sintering with Online Experiments and Phase-field Simulation
投稿时间: 2016-05-18  最后修改时间: 2016-05-27
DOI:
中文关键词:  混合金属  微波烧结机制  微结构演化  相场动力学模型  SR-CT技术
英文关键词:Mixed metal  Microwave sintering mechanism  Microstructure evolution  Phase field model  SR-CT technology
基金项目:国家自然科学基金项目(面上项目,重点项目,重大项目);国家重点基础研究发展计划(973计划)
作者单位E-mail
康丹 中国科学技术大学近代力学系 dank@mail.ustc.edu.cn 
许峰 中国科学技术大学近代力学系 xufeng3@ustc.edu.cn 
胡小方 中国科学技术大学近代力学系  
肖宇 中国科学技术大学近代力学系  
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中文摘要:
      合金材料具有优异的力学性能和广泛的应用范围,和传统方法相比,利用微波制备合金具有明显的优势。为了探索合金材料的微波烧结机制,本文采用合金领域关注度较高的Ti和Al混合金属样品,利用在线实验方式获得的样品在微波烧结时微观结构演化结果,和单质Ti和单质Al对比发现,混合Ti-Al样品的烧结温度明显降低,烧结速率显著增加。分析认为,Ti和Al之间形成了金属间化合物,由于该化合物和单质金属电导率不同,导致界面极化现象的产生,极化损耗导致界面处温度升高,提高了界面物质的扩散速度;同时,由于界面处物质扩散加剧,大量原子向烧结颈聚集,造成空位向晶界扩散,过饱和的空位被晶界上的位错歼灭,在该处生成牵引力,促使相邻颗粒之间产生对心刚体运动。利用理论分析的结果,在相场数值模拟中同时引入多种扩散机制和刚体运动项,修正密度场控制方程,并拟合烧结颈等微观结构参数随模拟时间的演化曲线,和实验结果基本一致,进一步验证了混合金属与微波产生了特殊作用,即驱动物质扩散的热效应和促使颗粒间向心运动的作用力,为研究合金体系在微波烧结过程中的演化机制提供支持
英文摘要:
      The mechanical properties of alloy are excellent, preparation of alloys by microwave is with more advantages than traditional methods. In order to explore the mechanism of microwave sintering alloy, metal Ti and Al were used as research subjects, microstructure evolution images during microwave sintering were obtained by online experiment. Compared with the elemental metal Ti and Al, sintering temperature of Ti-Al decreased obviously, and there was a significant increase in sintering rate. Because of the formation of intermetallic compound which made the conductivity decreased, the temperature increased by the interfacial polarization loss, and the rate of substance diffusion between the interface increased. Meanwhile, A large amount of vacancies moved to the grain boundary when the atoms gathered to the sintering neck, the over-saturated vacancies are annihilated by the dislocations at grain boundaries, producing an local force that pulls neighboring particles toward one another. By means of the theoretical analysis, diffusion function and rigid-body motions were introduced into the phase field simulation, which improved the control equations. By the curve of the sintering neck size and time, the simulation results was basically the same with the experiment, the special effects between the microwave and mixed metal were further verified, the special effects were thermal effects which drove the mass diffusion, and the force between the particles which made them move together.
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