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金属铝微波烧结微结构演化的在线观测与相场模拟
Investigation on Microstructural Evolution of Metal Al during Microwave Sintering by on-line Observation and Phase Field Simulation
投稿时间:2018-05-25  修订日期:2018-06-05
DOI:
中文关键词:  微波烧结 孔隙 同步辐射CT 相场动力学
英文关键词:microwave sintering  pore  Synchrotron radiation computed tomography (SR-CT)  phase-filed dynamics
基金项目:国家重点研发计划、国家自然科学基金、中央高校基本科研专项资金、安徽省自然基金
作者单位E-mail
许峰 中国科学技术大学近代力学系 xufeng3@ustc.edu.cn 
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中文摘要:
      材料内部微结构及其演化与材料宏观力学性能密切相关,而孔隙是微结构的一种重要形态。在金属粉末微波烧结过程中,由于烧结机理复杂,且受限于传统实验观测手段,目前对金属微波烧结孔隙演化机理的认识尚不清晰。本文采用SR-CT(Synchrotron Radiation Computed Tomography,同步辐射计算机断层扫描)技术对金属铝粉末微波烧结过程中的孔隙演化进行了在线观测,观测到呈条状的孔隙沿短轴闭合这一独特现象,与常规烧结中孔隙圆滑化和球化过程截然不同。基于这一现象,针对金属颗粒在微波电磁场作用下进行了受力分析,认为在微波电磁场中金属颗粒表面产生电子涡流,颗粒受到沿表面法线方向并指向孔隙内部的安培驱动力作用,促进了孔隙沿短轴方向的闭合,据此提出了条状孔隙演化的安培力驱动模型。将这一模型引入相场模拟,基于实验图像模拟孔隙的演化过程,得到了与实验一致的模拟结果,从而验证了安培力驱动模型的正确性。
英文摘要:
      The microstructure and its evolution are closely related to the macroscopic mechanical properties of materials, and the pore is one of the most important class of microstructure. In the process of metal powder microwave sintering, the mechanism of sintering is extremely complex, furthermore, there are many restrictions on the conventional observing method, the evolution mechanism of metal’s pore during microwave sintering is still uncertainly up to now. In this paper, the microstructrue evolution of aluminium powers is been observed in real time by Synchrotron Radiation Computed Tomography (SR-CT) technology, and the unique phenomenon of a long space pore closing along the minor axis is observed, which is far different from the process of spherification and spheroidization in conventional sintering. Analysis the force of metal particles under the action of microwave electromagnetic field based on the phenomenon, the paper consider that the eddy current generated on the bonding particle’s surface in microwave electromagnetic, and the particles are subjected to the ampere driving force which point to the normal direction of the surface, and accelerate closing of the pore. Based on this, an ampere force drive model of long space pore evolution is proposed. Introducing the model into phase field simulation, the evolution process of pores is simulated based on experimental images. It is shown that the results of the simulation are in accordance with the experiments, thus the theory of ampere force drive model is been confirmed.
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