Precipitation and recrystallization behavior of cold rolled CuTi alloy after aging in a wide range of temperature

Abstract

The microstructural evolution and property changes of cold-rolled Cu-4 Ti alloy during aging treatments at temperatures ranging from 300 °C to 800 °C for 20 min were systematically investigated. At temperatures below 400 °C, spinodal decomposition dominated, forming coherent Ti-rich regions and resulting in a peak tensile strength of 1115 MPa. Aging at 500 °C led to peak electrical conductivity of 14.7% IACS and activated partial recrystallization, forming metastable β'-Cu₄Ti precipitates in deformed regions and equilibrium β-Cu₄Ti precipitates in recrystallized regions. Complete recrystallization occurred above 600 °C, improving ductility significantly and increasing the uniform elongation to 32% at 800 °C. The intense cold rolling enhanced discontinuous precipitation via strain energy provision and accelerated the mass transport. The variation of mechanical and electrical properties with aging temperature was discussed, and mechanisms for the precipitation and recrystallization were revealed. This work elucidates the interplay between precipitation, recrystallization, and properties, enabling microstructure and property optimization in CuTi alloys.