At the 2010 Santa Fe Symposium®, Martyn Pugh and Dr. Ann-Marie Carey showed that 990 fine gold (1% titanium by weight) could be shaped and welded into a large jug. At the 2011 Santa Fe Symposium, this author explained how this alloy, designed to be a heat-treatable gold, survived highly skilled bench work, casting, and welding without heat treatment. It was not processed under equilibrium conditions, and the volumetric effect of 1% titanium by weight stretched its influence to 20% by volume. Silver produces a similar result but slightly different in detail from gold. There is an inter-metallic compound between silver and titanium, Ag-Ti, and it does have decreasing solid solubility but not such an extensive volumetric effect as Au4Ti. The density difference between silver and titanium is roughly half the difference with gold. To get a similar volumetric effect requires about 4% or 5% titanium in silver. Alloys have been made in the laboratory by powder metallurgy, 3D printing, co-cladding, and melting and casting, usually under argon. Silver volatilizes at sub-atmospheric pressures at the melting point of titanium. Titanium raises silver's ability to work harden, and the alloy can be age hardened to spring-like properties. Once evenly distributed within fine silver, the oxidation potential of titanium appears to be controllable. Under certain conditions it seems a transparent protective oxide film over the surface modifies the color slightly and delays tarnish.

Author(s): Dr. John C. Wright