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康丹,许峰*,胡小方,肖宇.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[J].实验力学,2018,33(1):41~48
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
Conjoint analysis of online experiment and phase field simulation for the effect of metal hetero interface on diffusion of microwave sintering
投稿时间: 2016-05-18  最后修改时间: 2016-06-27
DOI:10.7520/1001-4888-16-093
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  同步辐射断层扫描(SR-CT)技术
英文关键词:mixed metal  microwave sintering mechanism  microstructure evolution  phase field model  Synchrotron Radiation-Computed Tomography (SR-CT) technology
基金项目:国家自然科学基金项目(No.11272305, No.11172290, No.11472265, No.10902108), 973项目(No.2012CB937504),安徽省自然基金 (No.1508085MA17)共同资助
作者单位
康丹 中国科学技术大学 材料力学行为和设计重点实验室 安徽合肥 230027 
许峰* 中国科学技术大学 材料力学行为和设计重点实验室 安徽合肥 230027 
胡小方 中国科学技术大学 材料力学行为和设计重点实验室 安徽合肥 230027 
肖宇 中国科学技术大学 材料力学行为和设计重点实验室 安徽合肥 230027 
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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,与传统方法相比,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了样品在微波烧结时的微观结构演化结果。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。由上述现象分析认为,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。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。上述结果可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:
      Alloy material has excellent mechanical properties and wide application, compared with traditional method, it has obvious advantage to prepare alloy by microwave. In order to explore the mechanism of microwave sintering alloy materials, the Ti and Al mixed metal sample, which has high degree of concern in alloy domain, was adopted in this paper, microstructure evolution during microwave sintering was obtained by online experiment. By comparing with pure Ti and pure Al, it is found that the sintering temperature of mixed Ti-Al sample decreases significantly, and the sintering rate increases significantly. Analysis considers, intermetallic compound is formed between Ti and Al, which leads to interfacial polarization due to different conductivity. The polarization loss leads to the increase of temperature at interface and the diffusion rate of interface substance. Meanwhile, due to the intension of material diffusion at interface, a large number of atoms aggregates to sintering neck, resulting in the diffusion of vacancies to the grain boundary. Supersaturated vacancies are annihilated by the dislocations at grain boundaries, producing an local force that pulls neighboring particles toward one to another. Using the results of theoretical analysis, a variety of diffusion mechanism and rigid body motion were introduced, and the control equation of density field was modified, and the evolution curves of microstructure parameters such as sintering neck and so on were fitted. The curves and experimental results are basically consistent, which further verified that the mixture of metals and microwave produces a special effect, that is, the thermal effect driving material diffusion and the force acting on particle moving.Above results provide support for study of alloy evolution mechanism during microwave sintering process.
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