Correlation between grain boundary (GB) structure, GB fracture strength and GB energy in metals and covalentbonded materials

金属和共价键合材料中晶界 (GB) 结构、GB 断裂强度和 GB 能量之间的相关性

• 批准号: 06650782
• 负责人: TSUREKAWA Sadahiro
• 金额: $ 1.34万
• 依托单位: KYUSHU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1995
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06650782/
• 关键词: grain boundary; coincidence site lattice theory; O-lattice theory; grain boundary energy; high resolution electron microscopy; molybdenum; silicon; aluminum

The grain boundary (GB) property depends strongly on its character. Also, the mechanical properties such as the GB sliding and/or GB migration at high temperatures are affected by the GB character. In this investigation, the orientation controlled bicrystals of Al, Mo, TiC and Si were prepared, and the GBs have been systematically observed by the high resolution transmission electron microscopy to clarify the effect of the GB character or atomic bonding on GB structures. In addition to the TEM observation, the GB energy and its stregth were measured, then we have discussed the correlation between GB strength, GB energy and GB structure.1.Grain boundary structure : The grain boundaries were found to be consisted of the primary dislocation (lattice dislocations) array and the secondary one (DSC dislocation array) irrespective of the GB character and of atomic bonding except the case that the GB phase, which was often observed in covalent-bonded ceramics such as Si_3N_4, existed along the boundaries. These periodic structures would be probably described by the geometric models based on the O-lattice and the coincidence site lattice theories.2.Correlation between the GB energy and the GB dislocation density (GB structure) : It was seen that there existed good ocrrelation between the misorientation-dependence of GB energy and that of GB dislocation density, suggrsting that the main part of the GB energy must have been contributed by the elastic energy of GB dislocations. According to the Read-Shockley relation, the GB energy can be uniquely determined by the misorientation angle, though the relation is only valid in the range of small angle GBs. However, we found that it was possible to extend the relation to the range of high angle GBs by plotting against the GB dislocation density instead of the misorientation angle.Also, it was seen that the core energy of the GB dislocation was less dependent of the magnitude of its Burgers vector.

晶界的性质在很大程度上取决于晶界的性质。此外，机械性能，如高温下的GB滑动和/或GB迁移受GB特性的影响。本研究制备了Al、Mo、TiC和Si的取向控制双晶，并利用高分辨透射电子显微镜对晶界进行了系统的观察，以阐明晶界特征或原子键合对晶界结构的影响。除了透射电镜观察外，还测量了晶界能和晶界强度，讨论了晶界强度、晶界能与晶界结构之间的关系。1.晶界结构：晶界由初生位错组成（点阵位错）排列和二次排列（DSC位错排列），除了在共价键合陶瓷如Si_3N_4中经常观察到的晶界相沿着晶界存在的情况外，不考虑晶界特征和原子键合。这些周期性结构可以用基于O点阵理论和重合位点阵理论的几何模型来描述（GB结构）：结果表明，GB能与GB位错密度的取向差依赖性之间存在着良好的相关性，认为GB能的主要部分是由GB位错的弹性能贡献的。根据Read-Shockley关系，尽管该关系仅在小角度GBs范围内有效，但GBs能量可以由取向差角唯一确定。然而，我们发现，它是可能的，以扩大的范围内的大角度GB的关系，通过绘制对GB位错密度，而不是取向差角。此外，它被认为是GB位错的核心能量是依赖于其Burgers矢量的大小。

项目成果

田中 智昭: "モリブデン<110>対称傾角粒界の破壊強度と粒界エネルギーの方位依存症" 日本金属学会誌. 58. 382-389 (1994)

Tomoaki Tanaka：“钼<110>对称倾斜晶界的断裂强度和晶界能量的取向依赖性”日本金属学会杂志58. 382-389（1994）。

Sadahiro Tsurekawa: "Grain boundary migration in Fe-3% Sibicrystai" Proc. of the 2nd Inter.Conf.on Grain Growth in Polycrystalline Materials (ICGG-2). (1995)

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Koji Morita, Sadahiro Tsurekawa, Hideharu Nakashima and Hideo Yoshinaga: "Grain Boundary Structures in Covalent-Bonded Ceramics" Ceramic Transactions. Vol.44. 103-112 (1994)

Koji Morita、Sadahiro Tsurekawa、Hideharu Nakashima 和 Hideo Yoshinaga：“共价键陶瓷中的晶界结构”陶瓷交易。

Sadahiro Tsurekawa, Toshiyuki Ueda, Katsushi Ichikawa, Hideharu Nakashima, Yasunari Yoshitomi and Hideo Yoshinaga: "Grain Boundary Migration in Fe-3% Si Bicrystal" Proc.of the 2nd Inter.Conf.on Grain Growth in Polycrystalline Materials (ICGG-2). (1995)

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Sadahiro Tsurekawa: "Grain boundary migration in Fe-3% Si bicrysral" Proc. of the 2nd Inter. Conf. on Grain Growth in Polycrystalline Materials(ICGG-2). (in press). (1995)

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