On the properties of <111>{110} dissociated superdislocation in B2 structure YAg and YCu: Core structure and Peierls stress

doi:10.1007/s11706-009-0022-3

Front Mater Sci Chin

2009, Vol. 3

Issue (2) : 205-211 https://doi.org/10.1007/s11706-009-0022-3

RESEARCH ARTICLE

On the properties of <111>{110} dissociated superdislocation in B2 structure YAg and YCu: Core structure and Peierls stress

Xiao-zhi WU(

), Shao-feng WANG

Institute for Structure and Function, Chongqing University, Chongqing 400044, China

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Abstract

The simplified one-dimensional dislocation equation for mixed dislocations is derived briefly from the two-dimensional modified Peierls-Nabarro equation taking into account the discreteness effect of crystals. The collinear dissociated core structure of <111>{110} superdislocations in the novel B2 structure YAg and YCu are investigated with the simplified equation. Both the core width and the dissociated width are increasing with the increases in the dislocation angle of superdislocations. The dissociated width determined by continuum elastic theory is inaccurate for the high antiphase boundary energy but is recovered for the low antiphase boundary energy. The Peierls stress of the dissociated dislocation is replaced by that of superpartials. The results show that both the unstable stacking fault energy and the core width are crucial for the Peierls stress in the case of a narrow core structure. However, the core width becomes the main factor in controlling the Peierls stress in the case of a wide core.

Keywords core structure dissociation width variational method Peierls stress

Corresponding Author(s): WU Xiao-zhi,Email:xiaozhi3270@sina.com.cn

Issue Date: 05 June 2009

Cite this article:

Xiao-zhi WU,Shao-feng WANG. On the properties of <111>{110} dissociated superdislocation in B2 structure YAg and YCu: Core structure and Peierls stress[J]. Front Mater Sci Chin, 2009, 3(2): 205-211.

URL:

https://academic.hep.com.cn/foms/EN/10.1007/s11706-009-0022-3
https://academic.hep.com.cn/foms/EN/Y2009/V3/I2/205

Tab.1 Shear modulus , Poisson’s ratio , lattice parameters , antiphase boundary energy , and Δ of YAg and YCu

Fig.1 Generalized stacking fault energy curves along the <111> direction in the {110} slip plane of YAg and YCu; The corresponding restoring force of YAg and YCu

Tab.2 Core width , dissociated width (in units of ), and Peierls stress (in units of 10) at 0° (screw), 30°, 60°, and 90° (edge) superdislocations in YAg and YCu

Fig.2 The dislocation profile of the edge superdislocation in YAg obtained by the P-N equation and modified P-N equation; The corresponding dislocation density of the edge superdislocation

Fig.3 The dissociated width as a function of the antiphase boundary energy for the edge dissociated superdislocation in YAg

Fig.4 The changes in Peierls stress as a function of the core width for different antiphase boundary energy (taking YAg as an example)

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