Effect of direct current pulses on mechanical and electrical properties of aged Cu-Cr-Zr alloys

摘要

In this work, the response of Cu-Cr-Zr alloys to aging under direct current (DC) pulses was investigated. The results demonstrated that well-balanced mechanical properties and electrical conductivity can be achieved in case the alloys were properly treated. The aging behavior of Cu-Cr-Zr alloys is sensitive to DC pulses in the temperature range between 400 and 450 ℃ whereas at temperatures out of this range, DC pulses have minor influences. The hardness of aged Cu-Cr-Zr alloy is increased by DC pulses while the electrical conductivity is slightly decreased. The peak hardness is increased by 10 HV after aging at 400 ℃ for 1 h. With the imposition of DC pulses, the precipitate size of Cr rich precipitates in aged Cu-Cr-Zr alloys is reduced from 238 nm to 178 nm, exhibiting stronger Orowan strengthening. After aging at 450 ℃ for 2 h with DC pulses, the Cu-Cr-Zr alloy has an average tensile strength of 609 MPa, elongation of 12.8%, and electrical conductivity of 77.6% IACS. A retarding effect of DC pulses on precipitation process is confirmed by synchrotron X-ray diffraction analysis, which is responsible for the slight decrease in electrical conductivity.