Decomposition of deformed α′(α) martensitic phase in Ti-6Al-4V alloy

The process of martensitic alpha '(alpha '') phase decomposition in titanium alloys has not been sufficiently characterised in the literature - especially in terms of plastically deformed martensite. The research results of water-quenched Ti-6Al-4V alloy, subsequently cold deformed in compression test and tempered at the temperature range of 600-900 degrees C for 1 and 2 h were presented in the paper. Light and scanning electron microscopy observations revealed the influence of plastic deformation on tempered martensite laths morphology - particularly at the temperature of 900 degrees C - it favoured their fragmentation and spheroidisation. The effect of plastic deformation on characteristic temperatures of alpha '(alpha '')->alpha + beta phase transformation, phase composition and alloying elements distribution in phase constituents of Ti-6Al-4V alloy was identified and evaluated too. This paper is part of a thematic issue on Titanium. [GRAPHICS]