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Copper Based Alloy Properties

Jul 13, 2019

Copper alloys have good electrical and thermal conductivity, medium mechanical properties and high chemical stability, and poor cutting performance. The properties of various copper alloys vary greatly with the kinds and amounts of alloying elements added.


Copper alloy is a good conductor. The conductivity of pure copper ranges from 100% to 103% IACS (see copper for the definition of IACS). Addition of any solid solution alloying elements will reduce the conductivity of copper. The reduction of unit atomic concentration depends mainly on the effect of alloying elements on the lattice of copper, and increases with the increase of the addition amount in the solid solution range.

Color and lustre

Copper has a beautiful rose-red color. After adding zinc, aluminium, nickel and other alloy elements, the color changes to golden and silver, so it can be used to make various decorations and coins.

The strength of copper alloy is medium, and the tensile strength of industrial pure copper under annealing is about 240 MPa. The strength of copper alloys can be improved by solution strengthening, work hardening, precipitation hardening (including metastable decomposition), grain refinement and dispersion strengthening. Cold working can be used to harden alloys alone, and can be strengthened by precipitation hardening or metastable decomposition.

Adding any solid solution alloying element in copper will increase the strength of copper. The shear modulus of copper strengthened by unit atomic concentration is related to the difference between the added element and atomic size of copper.

Cutting ability of copper alloys is poor. Adding lead, sulfur, tellurium and other elements can improve the cutting ability of copper alloys. According to the machinability, deformed copper alloys can be divided into three categories: (1) free-cutting alloys with machinability of more than 70%, including free-cutting copper containing lead, sulphur or tellurium, free-cutting brass, various lead brass and bronze and zinc white copper containing about 2%; (2) medium-cutting alloys with machinability of 30%-60%, including 60%-85% copper. Brass and bronze and zinc bronze containing about 1% lead, etc.; (3) Hard-to-cut alloys with machinability below 20%, including low-zinc brass, zinc bronze, tin bronze, copper-nickel alloy and beryllium bronze (generally compared with 100% machinability of free-cutting brass).

Stress Relaxation Resistance

The stress relaxation resistance of pure copper is poor. Adding soluble elements which can improve the softening temperature or atomic size of copper is different from that of copper, can improve the stress relaxation resistance of copper. Beryllium bronze, white copper and zinc bronze have the best stress relaxation resistance, followed by tin bronze and tin brass, followed by silicon bronze, and ordinary brass has the worst stress relaxation resistance. As far as stress relaxation ability is concerned, the maximum service temperature of copper alloys is about 200 C. Brass with low stress relaxation resistance can only be used to make parts slightly higher than room temperature. Beryllium bronze and ternary copper-nickel alloys containing tin, silicon, aluminium or zinc have high stress relaxation resistance even at the highest temperature commonly used in current devices.

Company name:Hangzhou Ualloy Material Co.,Ltd
Address:No.126,Jincheng Road,Xindeng Town,Fuyang District,Hangzhou City,Zhejiang Province-311404
Contact:Michael Qiu
Contact phone number:86-571-63255636
Mobile phone:86-18072739736