Precipitation characteristics and strengthening mechanisms in an ultra-high Cu-Ti-Cr-Mg alloy

A Cu-4Ti-0.5Cr-0.5 Mg alloy, specifically designed to achieve superior strength and conductivity, was subjected to pre-aging, cold rolling, and final aging to improve its mechanical and electrical characteristics. Comprehensive evaluations of the microstructure and performance of the alloy were conducted using advanced techniques, such as TEM analysis, tensile testing, hardness measurements, and assessments of electrical conductivity (EC). The addition of Cr and Mg to Cu-Ti alloys led to the formation of Cr2Ti intermetallic compounds and suppressed the formation of the (3-Cu4Ti phase. After pre-aging, cold rolling, and the final aging treatment, the final alloy exhibited notable improvements, with a hardness of 362 HV, yield strength of 1080 MPa, tensile strength of 1200 MPa, and EC of 10.78%IACS, which are superior to those of direct cold rolling. The calculated contributions from diverse strengthening mechanisms harmonized effectively with the tensile results, underscoring the pivotal role of precipitation hardening facilitated by nanoscale alpha-Cu4Ti particles in Cu-Ti alloys.