Resistance of Diffusion-Bonded Electroless Nickel-Plated Ti-5Al-2.5Sn Alloy to Hot Salt Stress Corrosion Cracking.

摘要

Bent-beam, constant deflection experiments at a temperature of 900 F for time durations up to 1000 hours indicated that diffusion-bonded (950 F or 1150 F in vacuum) electroless nickel plate was affected by hot salt stress corrosion (HSSC). However, the protective plate demonstrated potential for reducing the susceptibility of the Ti-5Al-2.5Sn titanium alloy substrate to HSSC cracking. Mechanically induced surface defects (indentations, scratches) in the surface of the plate did not significantly alter the patterns of corrosion attack. Continued in-house efforts to establish failure mechanisms and to optimize plating processes are contingent upon results from further tests to determine erosion and fatigue behavior of these materials at elevated temperature.