History of Electrum. This gold-silver alloy has a long history of being used by humans. It was used for different purposes since third millennium BC. However, the variation in the gold and silver contents of this alloy made it difficult to decide the value of each coin.
Malleability is the ability of materials to deform easily under compressive stress. This can be often characterized as materials ability to form thin sheets by hammering or rolling. On the other hand, Ductility is the ability of materials to deform easily under tensile stress.
For the stiffness to weight ratio, see specific modulus. The specific strength is a material's strength (force per unit area at failure) divided by its density. It is also known as the strength-to-weight ratio or strength/weight ratio. In fiber or textile applications, tenacity is the usual measure of specific strength. The SI unit for specific strength is Pa /(kg / m 3), or N Â·m/kg, which is dimensionally equivalent to m 2 /s 2, though the latter form is rarely used.