Acid corrosion behaviour of Ti–48Al–6Nb porous alloys with different phase skeletons

Abstract

Ti–48Al–6Nb porous alloys with different phase skeletons were synthesised by powder metallurgy at different temperatures. TiAl₃ skeletons achieved at 700°C were covered by corrosion products and skeletons fractures led to pores collapse. TiAl skeletons were synthesised at 900°C with obvious corrosion pits and pore diameter increasing. And Ti₃Al/TiAl skeletons achieved at 1350°C exhibit the best acid corrosion resistance with the least mass loss of 1.853 mg m^–2. Skeletons and pore diameters remained stable just with fully lamellar structures emerged. In addition, Nb₂Al phases presented better resistance than NbAl₃ in the skeletons contributing to acid corrosion resistance of the porous alloys.

Keywords:

• Porous TiAl alloys
• Acid corrosion
• Pore structures
• Corrosion pits
• Mass loss

Acknowledgements

This research was supported by the National Natural Science Foundation of China (No. 51271016), the Beijing Natural Science Foundation (No. 2122043) and the National Basic Research Program of China (973 Program, No. 2011CB605500).