Microstructural evolution, compressive deformation and corrosion behaviour of thermally oxidized porous Ti4Al4Co alloy made of mechanically alloyed powder

Abstract

Abstract In the present work, porous Ti4Al4Co (0.56\xa0±\xa00.02 porosity) alloy samples were prepared through space holder technique using mechanically alloyed powder. Porous specimens having similar porosity were heat treated in open atmosphere at different heating time (10\xa0h, 20\xa0h and 30\xa0h) to investigate the microstructural evolution, compressive deformation and corrosion behaviour. XRD and Raman analysis confirm the formation of oxide (layer) due to heat treatment. Microstructural analysis reveals the phase evolution in the sample due to thermal heating. Compressive stress-strain diagram indicates that plastic collapse stress and densification strain reduce with increment of heating time, but elastic modulus slightly increases. Icorr reduced significantly due to heating and it is 25 times lower for the 30\xa0h heat treated sample than non-heat treated sample. In EIS curve, modulus of impedance and phase angle increase due to heat treatment which reveal that significant improvement in corrosion resistance occurs due to thermal heating.