Influence Of PM Processing Method On The Corrosion And Oxidation Behaviour Of A Low-cost Ti-Fe Alloy.

The design of titanium alloys by PM aims to obtain high performance/cost ratios in terms of mechanical properties. However, the corrosion behaviour of PM Ti alloys, although very important, is rarely studied. In this work the corrosion and oxidation behaviour of a Ti-7Fe alloy that has comparable tensile strength and hardness to those of the Ti-6Al-4V alloy, are evaluated. In particular, the corrosion behaviour of the as-sintered and extruded (after sintering) PM Ti-7Fe alloy was analysed via Electrochemical Impedance Spectroscopy (EIS) and polarization techniques in a Harrison solution (0. 35%w (NH4)2SO4 + 0.05 %w NaCl) to simulate aeronautic environment. The oxidation behaviour was studied in static air at 530°C and 600°C up to 300 h on the base of mass gain measurements. It was found that the as-sintered and extruded Ti-7Fe alloys have similar corrosion behaviour but the fully dense extruded material has better oxidation resistance.