【摘要】 金属材料中晶粒形态的演变是晶界迁移的结果,而晶粒形态又是决定材料性能的一个重要因素,因此,通过调控晶界迁移以获得目标组织成为工程研究关注的问题。本文综述了金属晶界迁移问题的研究,并给出了作者关于TiAl合金相关的研究进展:首先介绍了晶界迁移的现象及物理模型,然后分析了晶界迁移的驱动力,并着重说明扩散和应力驱动下的晶界迁移现象。其次,讨论了晶界迁移中的各种影响因素,包括取向差、晶界结点、曲率、温度和温度梯度等。最后,对晶界迁移调控在工程上的一些应用进行了介绍,特别讨论了其在TiAl合金中的应用,并结合作者的原位观察工作,对2种TiAl合金在高温单相区的晶界迁移现象进行了分析。更多还原

【Abstract】 The evolution of grain morphology is accompanied with grain boundary(GB) migration, and the grain morphology significantly determines the properties. Therefore, the key problem in engineering research is to obtain expected microstructures by controlling GB migration. The understanding on GB migration in metals was reviewed and the current study on TiAl alloys was given in this paper. Firstly, the phenomenon and physical model of GB migration were introduced. Then the driving force, especially the diffusion and stress, was analyzed. Secondly, the influence factors of GB migration were discussed, including misorientation, grain boundary triple junctions, curvature, temperature and thermal gradient. Finally, some applications of the regulation of GB migration were introduced. Combined with in-situ observation of the author, the GB migrations of TiAl alloys in single-phase regions at high temperatures were analyzed.更多还原