Application of Small Punch Techniques for the Determination of Gold Mechanical Properties

Gold has been one of the most valuable materials since ancient times. These days it is mainly used as a business commodity or as an engineering material in jewellery, medical prostheses (mainly dental) or electronics. For these engineering purposes, knowledge of its mechanical properties is a key factor in order to improve design and performance. The properties of pure gold have already been reported, although the information on them is scarce and indeed no information on properties such as fracture resistance has been found by the authors of this work. Gold alloys, especially those used for dental implants, are better characterised, but the development of new alloys requires a new characterisation of their properties. At the same time, there have been important advances in recent years in the development of non-destructive or quasi-non-destructive techniques for the mechanical characterisation of materials. Among these, the small punch technique has proven to be one of the most reliable and efficient (in terms of material consumption). This technique is here applied for the determination of 24 (pure gold) and 18 (75% gold) carat gold properties, as an example of how this experimental tool is capable and suitable for the characterisation of gold, gold alloys and any other scarce, valuable material. The estimated tensile properties of 24 carat gold correlate well with the values observed in the literature, obtained through traditional test techniques.