Effect of special rotational deformation on dislocation emission from a semielliptical blunt crack tip in nanocrystalline solids

2013 ◽  
Vol 28 (6) ◽  
pp. 798-805 ◽  
Author(s):  
Min Yu ◽  
Qihong Fang ◽  
Hui Feng ◽  
Youwen Liu

Abstract

1995 ◽  
Vol 409 ◽  
Author(s):  
J. SchiØtz ◽  
A. E. Carlsson ◽  
L. -M. Canel ◽  
Robb Thomson

AbstractTheories of toughness of materials depend on an understanding of the characteristic instabilities of the crack tip, and their possible interactions. In this paper we examine the effect of dislocation emission on subsequent cleavage of a crack and on further dislocation emission. The work is an extension of the previously published Lattice Greens Function methodology[1, 2, 3]. We have developed a Cavity Greens Function describing a blunt crack and used it to study the effect of crack blunting under a range of different force laws. As the crack is blunted, we find a small but noticeable increase in the crack loading needed to propagate the crack. This effect may be of importance in materials where a dislocation source near the crack tip in a brittle material causes the crack to absorb anti-shielding dislocations, and thus cause a blunting of the crack. It is obviously also relevant to cracks in more ductile materials where the crack itself may emit dislocations.


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