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(GB)性质与其性质密切相关。此外，高温下的GB滑动和/或GB迁移等力学性能也受GB特性的影响。本研究制备了Al、Mo、TiC和Si的取向控制双晶，并用高分辨电子显微镜系统地观察了晶界结构，以阐明晶界性质或原子键对晶界结构的影响。此外，还测量了晶界能量及其强度，并讨论了晶界强度、晶界能量与晶界结构之间的关系。1.晶界结构：晶界结构：晶界由一次位错(晶格位错)阵列和二次位错(DSC位错阵列)组成，与晶界结构无关，晶界存在原子键，但在Si_3N_4等共价键合陶瓷中常见的晶界相沿晶界存在。这些周期结构可以用基于O晶格和重合格点理论的几何模型来描述。2.GB能量与GB位错密度(GB结构)的关系：可以看出，GB能量与GB位错密度之间存在着良好的关系，推测GB能量的主要部分一定是由GB位错的弹性能贡献的。根据Read-Shockley关系，虽然该关系只适用于小角度的Gb，但它可以唯一地确定Gb的能量。然而，我们发现，通过与GB位错密度而不是错向角作图，可以将关系扩展到高角度GBs的范围。此外，我们还发现GB位错的核心能量不太依赖于其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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