Self-organization processes in the cellular structure formation of Ni-W alloys

The self-organization processes, the growth steadiness, and the stability of the cellular structure morphology of Ni-W alloy single crystals with a tungsten concentration of 25–40% have been investigated. The temperature gradient in the crystallization front, the oriented crystallization rate, doping with aluminum, titanium, chromium, and molybdenum, and the tungsten concentration have been considered as nonequilibrium factors. The nonlinear dependence of the structure characteristics on the growth parameters, including the temperature gradient, the oriented crystallization rate, and the tungsten concentration, has been determined. Dendrite features of the cellular morphology of the crystallization front are the result of the self-organization processes and promote the steady growth of single crystals with a high degree of structural perfection. A mechanism of the morphological transition from hexagonal to square cells has been proposed.