Critical resolved shear stress

Critical resolved shear stress is the component of shear stress, resolved in the direction of slip, necessary to initiate slip in a grain. It is a constant for a given crystal.

Tests have been conducted on single crystals of metals to measure the shear stress required to initiate plastic deformation, or cause atomic planes to slip. Since this is a threshold value, it is referred to as critical; and since it is a component of the applied force or stress, it is said to be resolved; that is, the critical resolved shear stress.

Resolved shear stress is given by τ = σ cos Φ cos λ where σ is the magnitude of the applied tensile stress, Φ is the angle between the normal of the slip plane and the direction of the applied force and λ is the angle between the slip direction and the direction of the applied force. whereas, critical resolved shear stress value is given by τ =σ (cosΦ cosλ)max

Difference between RSS & CRSS

Resolved shear stress is the shear component of an applied tensile (or compressive) stress resolved along a slip plane that is other than perpendicular or parallel to the stress axis. The critical resolved shear stress is the value of resolved shear stress at which yielding begins; it is a property of the material.