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The precipitation hardening in Ni-based superalloys, which contain up to 73% volume fraction of γ', has been investigated by large scale 3D dislocation dynamics simulations. Dislocations glide under external stress across a {111} plane of γ/γ'phase, intersected by cubic γ'precipitates. The critical resolved shear stress (CRSS) has been investigated for different microstructureal parameters: γ'volume fraction, anti-phase boundary (APB) energy and channel width. It is shown that the CRSS depends on the square root of the volume fraction of γ'. The CRSS is linearly proportional to the APB energy. Stuctures with a non-uniform distribution of γ'have CRSS that is 20%-30% smaller than a stucture with unique γ'size corresponding to the average size of the non-uniform disribution of γ'. The fact is that the channel width is not uniform and some channel width is larger than the average channel width of a stucture with a non …