Processing method of Cu alloy to get high coincident site lattice ratio grain boundaries

Problem: The most effective Grain Boundary Engineering (GBE) technologies reported to date involve many cycles of cold work/hot annealing, which would be especially inefficient in practice at large scales. Technology: This invention is a new method of changing the internal structure of metals through a process of deformation and annealing. It pertains to changing the crystallographic types of grain boundaries to increase the fraction of ΓÇ£specialΓÇØ grain boundaries and to tailor desirable physical and chemical properties in metals. Instead of running cycles of “deformation at ambient temperature” and “annealing at apparently higher temperature than ambient temperature”, the new isothermal thermo-mechanical process can help avoid time and energy-consuming heating or cooling steps. The recent development of this technology proposes a new process of GBE. It is applied to Cu alloys that exhibit second-phase precipitation, and provides an appropriate GBE process for those alloys. Christopher Noble crn@mit.edu