For decorative applications a gold-steel composite material was manufactured by forging. Sheets made of steel K110, with a thickness of about 0.8 mm, and gold sheets, with a thickness of about 0.5 mm, were put together and forged approximately at 800 °C. Afterwards this bar was twisted in hot stage (Figure 1a). To obtain a 4 mm thick composite sheet two longitudinal cuts were performed. The end pieces of this bar were examined by metallography.
Forging of different steels together is called Damascus technique, forging different non-ferrous metals is called Mokume Gane, but there is no proper name for the composite made of gold or copper and steel.
The steel K110 shows deformation structures, because broken carbides are detected (Figure 1c, d). Earlier this was observed as well in medical drills.
The soft gold was partially pushed out at the ends of the sample (Figure 1b). The grain size in gold can reach up to 1 mm (Figure 1e, f). It is supposed that gold recrystallizes during cooling after the hot treatments.
An approximately 10 µm thick diffusion zone can be seen at the interfaces between steel and gold. According to the phase diagram at 800 °C 20 wt.% Fe is approximately soluble in gold and about 3 wt.% Au in iron.
The production of this gold-steel composite has thus succeeded in a satisfactory manner.