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There is a great parallel between metals and our civilized history. The use of a particular metal in day-to-day activities reflected the course of technology during a period of history and, quite often, influenced the rate at which a particular civilization advanced. Indeed, the metal copper has had a long, varied and extremely interesting history. Accordingly, it has served as the signpost of technological development over the centuries.Copper was the first metal that man used for tools and implements. It is conceivable that the primary reason for the early development of practical applications for this versatile metal was that copper, like gold and silver, is sometimes found in a pure state. As such, it can be beaten into shape even when cold. The earliest use of copper was by the Sumerians and Egyptians some 7,000 years ago. Long before Europeans reached the continent of North America, American Indians were using copper for beads and tools. Today, copper and copper alloys are used extensively in the manufacture of a multitude of applications - electric power, water supply, air cooling, telecommunications, computers, consumer products and countless electronic devices. Copper is the most widely used of all metals for today's diverse technologies. Copper is not only widely used but also simple to use. It is easily worked and ductile. It has pleasing color and luster, and forms alloys readily with many metals, increasing its versatility. There are more than 100 copper alloys, including zinc-brasses, tin- bronzes, nickel silvers and cupro nickels. Choice among the alloys in the copper-based system is one with slightly less than 2 percent beryllium (Be). The beryllium allows this alloy to be processed into strength levels higher than all other copper alloys. Beryllium is an alkaline earth metal. As an ore, beryl, or aluminum beryllium silicate, is a hexagonal crystal and contains as much as 15 percent beryllium. It is mined sometimes with aquamarine (a blue beryl) and emerald. In its metal form, it is the lightest of all the rigid metals and among the strongest. It has very high resistance to heat and corrosion, a very precise elastic limit, low mass atomic absorption, high infrared reflectivity and conductivity equal to that of aluminum. Accordingly, alloys of beryllium and copper have become technology's material of choice in the manufacture of electrical and thermal conducting springs because of their strength, heat dissipation and resistance to fatigue. Beryllium-copper alloys have desirable properties facilitating their use in a variety of demanding applications. However, it is not commonly realized that there are two distinct families of properties. The first is high strength, and the second is high conductivity. The high-strength alloys (C17200 and C17000) are less dense (.298 lbs./cu. in.) than conventional specialty coppers. This often results in a yield of up to 7 percent more feet per pound than high-strength phosphor bronze. The high-conductivity beryllium-copper alloys (C17500 C17510 and C17410) are ideally suited to applications requiring high operating temperatures, or high strength and conductivity. The following are specific beryllium-copper alloy advantages: High strength-to-weight ratio High electrical and thermal conductivity Long service life Wide range of mechanical properties Wide range of tempers High resistance to stress relaxation High fatigue strength Good corrosion resistance Resistance to anelastic behavior
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