(1) All elements, without exception, reduce the conductivity and thermal conductivity of copper bars. Any element that solidly dissolves in the copper bar causes lattice distortion, resulting in wave scattering when free electrons flow directionally, increasing the resistivity. On the contrary, elements with little or no solid solubility in the copper bar have little effect on the conductivity and thermal conductivity of the copper bar. It should be noted that some elements have a drastic decrease in solid solubility with decreasing temperature in the copper bar, The precipitation of elemental and metal compounds can not only strengthen copper bar alloys through solid solution and dispersion, but also minimize the decrease in conductivity. This is an important alloying principle for studying high-strength and high conductivity alloys. It should be particularly pointed out that alloys composed of iron, silicon, zirconium (not wrong), chromium and copper bars are extremely important high-strength and high conductivity alloys; Due to the superimposed effects of alloying elements on the performance of copper bars, CoCr Zr series alloys are well-known high-strength and high conductivity alloys.
(2) The microstructure of copper based corrosion-resistant alloys should be single-phase to avoid electrochemical corrosion caused by the presence of a second phase in the alloy. The alloy elements added for this purpose should have a high solid solubility in copper rods, even infinitely miscible elements. In engineering applications, single-phase brass rods, bronze rods, and white copper rods all have excellent corrosion resistance and are important heat exchange materials.
(3) Both soft and hard phases exist in the microstructure of copper based wear-resistant alloys. Therefore, during alloying, it is necessary to ensure that the added elements not only dissolve in the copper rod, but also precipitate hard phases. Typical hard phases in copper rod alloys include Ni3Si, FeALSi compounds, etc., and the a phase should not exceed 10%.
(4) Copper bar alloys with polycrystalline transformation in the solid state have damping properties, such as Cu Mn series alloys, and alloys with thermoelastic martensitic transformation in the solid state have memory properties, such as Cu Zn Al and Cu Al Mn series alloys.
(5) The color of copper bars can be changed by adding alloying elements, such as zinc, aluminum, tin, nickel, etc. As the content changes, the color also changes from red to blue, yellow to white. Reasonable control of the content will obtain imitation gold materials and imitation silver alloys.
(6) The elements selected for the alloying of copper bars and alloys should be commonly used, inexpensive, and pollution-free. The added elements should follow the principle of multiple elements and small amounts. The alloy raw materials can be comprehensively utilized, and the alloy should have excellent process performance, suitable for processing into various finished and semi-finished products.
