Fabrication of bulk single crystals via texture-engineered grain growth

Abstract

Single crystals have grain boundary-free structure and possess superior properties; thus, they are in great demand in industry. Conventional melt-based single-crystal growth methods are dominated by strict and complicated processes, usually leading to small and expensive single crystals. Here, we report a solid-based approach, namely “texture-engineered grain growth,” for preparing bulk single crystals in a controllable and cost-efficient manner. Using copper as an example, we show that deformation texturing can effectively induce abnormal grain growth of cold-drawn copper bars during recrystallization, in which {111} grains grow preferably by coalescing neighboring small grains. Moreover, the applied temperature gradient enables the as-formed abnormally large grain to act as a seeding crystal to expand directionally throughout the entire textured copper bar, readily converting the textured polycrystals into a bulk single crystal. The technique is also applicable to the growth of bulk single-crystal nickel. The texture-induced monocrystallization strategy would advance large-scale manufacturing and applications of bulk single crystals.