Properties of Beryllium Copper

Beryllium copper, also known as beryllium copper, CuBe, or beryllium bronze, is a metal alloy of copper and 0.5% to 3% beryllium, sometimes with other alloying elements, that has remarkable metalworking and handling qualities.

Beryllium copper is a ductile, weldable, and machinable alloy. It is resistant to non-oxidizing acids (such as hydrochloric acid or carbonic acid), plastic decomposition products, wear, and abrasion. In addition, it can be heat treated to increase its strength, durability, and electrical conductivity.

Because beryllium is toxic, there are some safety issues with handling its alloys. In solid form and as a finished product, beryllium copper is not particularly hazardous to health. However, inhalation of dust formed during machining or welding may cause severe lung damage. Beryllium compounds are known human carcinogens when inhaled. Therefore, beryllium copper is sometimes replaced by safer copper alloys, such as Cu-Ni-Sn bronze.

Beryllium copper is used for springs and other parts that must retain their shape during repeated strain. Because of its electrical conductivity, it is used for low-current contacts in batteries and electrical connectors. And because beryllium copper does not produce sparks but is physically tough and nonmagnetic, it can be used to make tools that can be used in explosive environments or for EOD purposes. A variety of tool types can be used, such as screwdrivers, pliers, wrenches, cold chisels, and hammers. Another metal that is sometimes used for non-sparking tools is aluminum bronze. Beryllium copper tools are more expensive, not as strong, and wear out faster than steel tools. However, the advantages of using beryllium copper in hazardous environments outweigh these disadvantages.

Beryllium copper is also often used to make professional-quality percussion instruments, especially tambourines, and triangles, which are highly regarded for their clear tone and strong resonance. Unlike most other materials, instruments made from beryllium copper will maintain a consistent pitch and timbre as the material resonates. The "feel" of these instruments is rich and melodious, to the point that they would seem out of place when used in the darker, more rhythmic sounds of classical music.

Beryllium copper is also used in ultra-low temperature cryogenic equipment, such as dilution refrigerators because it combines mechanical strength with relatively high thermal conductivity in this temperature range.

Beryllium copper is also used in armor-piercing bullets, although any such use is uncommon, as bullets made from steel alloys are much cheaper, but have similar properties.

Beryllium copper is also used in measurement while drilling tools in the directional (angled drilling) industry. A couple of companies that make these tools are GE (QDT Tensor Positive Pulse Tools) and Sondex (Geolink Negative Pulse Tools). Since magnetometers are used for calculations received from the tool, a non-magnetic alloy is required.

High-strength beryllium copper alloys contain up to 2.7% beryllium (cast), or 1.6-2% beryllium, and about 0.3% cobalt (wrought). High mechanical strength is achieved by precipitation hardening or age hardening. The thermal conductivity of these alloys is between that of steel and aluminum. Cast alloys are often used as materials for injection molds. The wrought alloys are designated by the UNS as C172000 to C17400 and the cast alloys as C82000 to C82800. The hardening process requires rapid cooling of the annealed metal, resulting in a solid solution of beryllium in the copper, which is then held at 200-460°C for at least one hour to promote the precipitation of metastable beryllium crystals in the copper matrix. Averaging is avoided because the formation of an equilibrium phase would consume the beryllium crystals and reduce the strength enhancement. The beryllium in the cast and wrought alloys is similar.