A Comparison of Ingot and Powder Metallurgy Production Routes on the Statistical Variability of the High Strength Ti-10-2-3 Titanium Alloy Tensile Properties

摘要

There has been concern over the level of variability of the mechanical properties of some titanium alloys, especially those with a notional high strength. High variability leads to significant reductions in the design allowable stresses and this can negate any benefit from the higher strengths of alloys like the near β Ti-10-2-3 alloy. There are a number of possible causes for this variability but chemical inhomogeneities are thought to be a significant contributor. In the work reported here a conventional ingot metallurgy and forged billet of Ti-10-2-3 has been compared with a powder metallurgy / hot isostatically pressed billet, in terms of the statistical variability of their tensile properties. Great care has been taken in minimising other potential factors, like heat treatment / cooling rates. This work has shown a 40-60% reduction in the statistical variability of the tensile properties of Ti-10-2-3 produced by powder metallurgy, compared with the ingot metallurgy material.