From Wikipedia
As beryllium is toxic there are some safety concerns for handling its alloys. In solid form and as finished parts, beryllium copper presents no particular health hazard. However, breathing its dust, as formed when machining or welding may cause serious lung damage. [1]Beryllium compounds are known human carcinogens when inhaled. [2] As a result, beryllium copper is sometimes replaced by safer copper alloys such as Cu-Ni-Sn bronze.[3]
[edit]Uses
Beryllium copper is used in springs and other parts that must retain their shapes during periods in which they are subjected to repeated strain. Due to its electrical conductivity, it is used in low-current contacts for batteries and electrical connectors. Because Beryllium copper is non-sparking but physically tough and nonmagnetic, it is used to make tools that can be used in extremely cold environments like Antarctica. Various tool types are available eg screwdrivers, pliers, spanners, cold chisels and hammers [4]. Another metal sometimes used for non-sparking tools is aluminium bronze. Compared to tools made of steel, Beryllium copper tools are more expensive, not as strong and wear out more quickly. However, the advantages of using Beryllium copper in hazardous environments outweigh these disadvantages.
Example of a non-sparking tool
Beryllium copper is also frequently used in the manufacture of professional-quality percussion instruments, especially tambourine and triangle, where it is prized for its clear tone and strong resonance. Unlike most other materials, an instrument composed of beryllium copper will maintain a consistent tone and timbre for as long as the material resonates. The "feel" of such instruments is rich and melodious to the point that they seem out of place when used in darker, more rhythmic pieces of classical music.
Beryllium copper has also found use in ultra-low temperature cryogenic equipment, such as dilution refrigerators, because of its combination of mechanical strength and relatively high thermal conductivity in this temperature range.
Beryllium copper has also been used for armour piercing bullets, [5] though any such usage is unusual because bullets made from steel alloys are much less expensive, but have similar properties.
Beryllium copper is also used for measurement-while-drilling tools in the directional (slant drilling) drilling industry. A few companies manufacturing these tools are GE (QDT tensor positive pulse tool) and Sondex (Geolink negative pulse tool). A non-magnetic alloy is required as magnetometers are used for calculations received from the tool.
For a time, beryllium copper was also used in the manufacture of golf clubs, with emphasis on wedges and putters. Many golfers prefer the soft feel of BeCu club heads, particularly for chip shots and putts around and on the green, where an extra measure of control is desired. Due to regulatory issues and high costs, BeCu clubs are hard to find in current production. Vintage and pre-owned examples remain in demand at used club shops and on Internet auction sites.