Upgrading the performance of functional Cu–Cr–Zr alloys for resistance welding electrodes

Abstract

The gravity die casting method was used to produce functional Cu–Cr–Zr alloys with various compositions. The functional electrical, mechanical, and wear properties of Cu–Cr–Zr alloys were studied at different aging times at 500°C. The optimum aging time that results in the best combination of hardness and functional electrical properties changes with the chemical composition of the alloys; the alloys with higher Zr content require a longer time to attain peak hardness. Complicated wear mechanisms are active in the Cu–Cr–Zr alloys. The alloys with the highest Zr and Cr contents exhibit the highest hardness and tensile strength with low wear resistance. The best Cr content is found to be just below the solubility limit at the solutionizing temperature.

Tailoring the composition of the functional Cu–Cr–Zr–La/Ce alloys for electromechanical applications

“…Because of its inferior mechanical properties, a diversity of copper alloys with improved mechanical properties have been produced to satisfy the market's needs in different electromechanical applications. Regrettably, electrical conductivity is usually inversely proportional to strength [1][2][3][4][5]. Almost all the hardening parameters in the metallic structure, such as dislocation, solid solute atoms, and grain boundaries, which serve as the obstacles to hinder the dislocations motion, result in lattice distortions.…”

“…Cu-Cr-Zr alloys have attractive integration of mechanical and functional electrical properties, so they are classified as functional materials [1,2,4]. These alloys are commonly used in the manufacture of electrochemical components, such as motor and high-speed railway contact materials [1,4,6,7].…”

“…The precipitate characteristics, electrical conductivities, and mechanical properties of various functional Cu-Cr-Zr alloy compositions, with and without rare earth element additions, were studied after aging at temperatures ranging from 250 to 600°C for periods ranging from 0 to 24 h [1,2,6,8,9,[11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. All studies concluded that achieving the best integration of high electrical conductivity, high strength, high hardness, and high wear resistance can be achieved via tailoring the processing parameters and chemical composition.…”

“…As the functional Cu-Cr-Zr alloy is a precipitation-hardened alloy, a Cr-and Zr-supersaturated Cu matrix is formed after solution treatment. On subsequent aging, Cr-and Zr-rich phases precipitate out of the supersaturated solid solution as fine precipitates of rich-component phases or intermetallic compounds [1,4,6,9]. The size, distribution, fraction, and coherency of the formed precipitates in the Cu matrix play the main role in adjusting the electromechanical properties of the Cu-Cr-Zr alloys [1,[6][7][8][9][10].…”

“…On subsequent aging, Cr-and Zr-rich phases precipitate out of the supersaturated solid solution as fine precipitates of rich-component phases or intermetallic compounds [1,4,6,9]. The size, distribution, fraction, and coherency of the formed precipitates in the Cu matrix play the main role in adjusting the electromechanical properties of the Cu-Cr-Zr alloys [1,[6][7][8][9][10]. These precipitate characteristics mainly depend on the chemical composition, aging temperature, and aging time.…”