The Critical Resolved Shear Stress CRSS in Ceramics

4 The Critical Resolved Shear Stress (CRSS) in Ceramics 

Slip is aided by dislocation movement. Dislocations (discussed in Chap. 3) may have a dual effect on the strength of materials. In the presence of a few dislocations, materials deform at a low-yield stress, tq, whereas, when the concentration 

In crystals, slip starts on specihc planes and in dehnite crystallographic directions at some critical value, known as the critical resolved shear stress (CRSS, discussed below). In the following, the minimum stress required for deformation by initiating slip is derived with the aid of Fig. 4.15. 

Slip occurs on the slip plane indicated by the dashed area and may be expressed as  

In terms of stress, the resolved shear stress in the slip plane in the slip direction obtained from Eqs. (1.4a) and (4.4) is  

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