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Investigation of grain boundary dynamics in metals

金属晶界动力学研究

基本信息

批准号：
220610523
负责人：
Professor Dr. Dmitri A. Molodov
金额：
--
依托单位：
Institut für Metallkunde und Metallphysik (IMM)
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2012
资助国家：
德国
起止时间：
2011-12-31 至 2018-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/220610523?language=en
关键词：
Investigation grain boundary dynamics metals

项目摘要

Hereby we apply for funding of the second phase of the research project , which originally started in 02/2013. By combining experimental investigations of structurally different grain boundaries in specially grown bicrystals of aluminum and copper as well as molecular dynamics simulations, the proposed research will further advance the understanding of grain boundary migration induced by various driving forces during microstructure evolution in metallic materials. The proposed program consists of three parts. In the first one, our investigation of stress induced grain boundary migration shall be continued. During the first phase of the project, an experimental setup has been constructed, which allows the in situ investigation of bicrystalline samples subjected to a pure shear stress at elevated temperatures. Using this setup, it is planned to compare grain boundary migration induced by a shear stress with such induced by tensile stress. The acquired data will allow for verification, or if needed improvement, of the existing model of stress induced grain boundary migration coupled with shear deformation. The same setup will then be used at a higher mechanical stress to investigate rigid gliding of the grains along the boundary plane (grain boundary sliding). In the second part the investigation of special Sigma 3 CSL tilt grain boundaries, which have the same geometry as coherent or incoherent twin boundaries, is planned. During the first phase of the project boundaries of this type have been investigated under capillary driving force and a similar behavior as for symmetrical low angle tilt grain boundaries was observed. Now this study shall be completed by investigation of the same Sigma 3 CSL tilt grain boundaries under stress induced driving force and of mixed boundaries with tilt as well as twist components which still fulfill the Sigma 3 CSL relationship. Boundaries of mixed type are the most common in real microstructure and for low ange grain boundaries were found out to behave strongly different than those with pure tilt geometry. So, the similar effects on the kinetics of the Sigma 3 CSL boundaries are expected as well. The third part will deal with the investigation of isolated grains during shrinkage at elevated temperatures. A special bridgman type furnace, allowing the growth of bicrystals with such isolated grains embedded in a monocrystalline matrix, is under construction and will be completed until the end of the ongoing first project phase. Systematic experimental investigation of the bicrystals at elevated temperartures will then be conducted to verify MD simulations of shrinking grains which have been conducted already and imply a strong effect of the orientation between grain and matrix on shrinking rate, shape evolution and grain rotation.

在此，我们申请资助该研究项目的第二阶段，该项目最初于2013年2月开始。通过对特殊生长的铝和铜双晶中不同晶界的实验研究和分子动力学模拟相结合，将进一步加深对金属材料微观组织演化过程中不同驱动力引起的晶界迁移的理解。拟议的计划由三个部分组成。在第一章中，我们将继续研究应力诱导的晶界迁移。在该项目的第一阶段，已经建立了一个实验装置，允许在高温下对承受纯剪切应力的双晶样品进行现场研究。利用这一装置，计划比较由剪应力引起的晶界迁移和由拉应力引起的晶界迁移。获得的数据将允许验证或如果需要改进现有的应力诱导晶界迁移与剪切变形耦合的模型。然后，在较高的机械应力下，使用相同的装置来研究颗粒沿晶界平面的刚性滑动(晶界滑动)。在第二部分中，计划对特殊的Sigma 3CSL倾斜晶界进行研究，这种晶界与共格或非共格孪晶具有相同的几何形状。在项目的第一阶段，在毛细驱动力下对这种类型的晶界进行了研究，观察到了与对称小角度倾斜晶界类似的行为。现在，本研究将通过研究在应力诱导驱动力作用下相同的Sigma 3CSL倾斜晶界和仍然满足Sigma 3CSL关系的倾斜和扭转成分的混合晶界来完成。在实际组织中，混合型晶界是最常见的，对于低角度晶界，其行为与纯倾斜几何形状的晶界有很大的不同。因此，对西格玛3CSL边界动力学的类似影响也是可以预期的。第三部分将讨论高温收缩过程中孤立颗粒的研究。一种特殊的布里奇曼式加热炉正在建设中，该加热炉允许生长双晶，将这种孤立的颗粒嵌入单晶基质中，并将一直完成到正在进行的第一阶段项目结束。然后对高温下的双晶进行系统的实验研究，以验证已经进行的双晶收缩的MD模拟，揭示了颗粒与基质之间的取向对收缩速率、形状演变和颗粒旋转的强烈影响。