| The high-elasticity of 18-karat gold bracelet has been tested by means of measuring the elasticity modulus and microstructure. It is shown that there are four phases, AuCu, AuCu3 and Au3Cu and (Au,Cu), in 18-karat gold. AuCu, AuCu3 and Au3Cu are ordered phases produced from the disordered (Au,Cu) phase through the transformation from a disorder to an order state as the temperature declines. The content of the ordered phases is up to 70%, which is a possible reason of high-elasticity. In addition, the elasticity modules of the surface and longitudinal section are different, and each phase has certain texture in the alloy, leading to the anisotropy of elasticity modulus. |
