TEM evidence of various glide modes in experimentally strained CuFeS₂ crystals

Abstract

TEM studies at 200°C (0.41 T_m) on experimentally deformed chalcopyrite (CuFeS₂) single crystals reveal a variety of structural defects in the planes {112}, (001) and {100}.

In {112} several glide modes have been identified. The majority of dislocations in {112} have (presumably) b = 1/2<311> and are accumulated in separated slip bands of high dislocation density. Line directions and dissociation modes of these dislocations depend on the orientation of the applied stress. Dislocations of the slip mode {112} <311>, mainly parallel to <110> or <021>, are dissociated into three non-collinear partials. Dislocations of the slip mode {112} <311>, often parallel to <111>, are dissociated into four non-collinear partials.

Dislocations of the subordinate slip mode {112} <111> with b = 1/2 {111} commonly are screws, dissociated into three collinear partials. Perfect dislocations with b = <211> seem to decompose into pairs of perfect dislocations with b = 1/2<311> and b = 1/2<111>. Dislocations with b = <110> enter {112} by cross slip from (001). The twinning mode {112}<111> develops from the movement of dislocations with b = 1/6<111>.

Dislocations of the slip mode (001)<111> are generally split into two collinear partials. Cross slip into {112} takes place with or without recombination of the partials. The slip mode {100}⟨010⟩ has been activated in the surroundings of high-density {112} slip bands. Dislocations with b = ⟨010⟩ form square loops with long segments along ⟨021⟩ and are split into two non-collinear partials b = 1/4⟨021⟩.

Models of the dissociation of the diverse perfect dislocations are discussed.