A ZONAL DISLOCATION MECHANISM FOR RHOMBOHEDRAL TWINNING IN SAPPHIRE (ALPHA-AL2O3)

被引：43

作者：

GEIPEL, T

LAGERLOF, KPD

PIROUZ, P

HEUER, AH

机构：

[1] Department of Materials Science and Engineering, Case Western Reserve University, Cleveland

来源：

ACTA METALLURGICA ET MATERIALIA | 1994年 / 42卷 / 04期

关键词：

D O I：

10.1016/0956-7151(94)90154-6

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

HRTEM investigations of rhombohedral twins in sapphire (alpha-Al2O3) indicate that they are ''screw twins''; the twin axis eta1, is [0111BAR] and involves a 1/6[0111BAR] translation in addition to the 2-fold rotational symmetry. Based on this data, a zonal dislocation mechanism for rhombohedral twinning in sapphire is proposed which predicts the correct shear strain s =0.202. This mechanism only requires movements of the Al and 0 ions of less than 50% of the closest Al-Al or O-O distances in the ideal crystal, although some ions have to move against the shear.

引用

页码：1367 / 1372

页数：6

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