Communication à un colloque
Résumé : In this work, the work hardenability of Ti-6Al-4V alloy has been investigated using a quenching and partitioning strategy on dual-phase Ti-6Al-4V samples. Indeed, it was recently demonstrated that a sub-transus thermal treatment followed by water quenching could generate a dual phase a + a’ microstructure displaying a high work-hardening capacity and leading to a promising increase in both strength and ductility.In the present work, we performed a series of ‘quenching’ treatments using several sub-transus solutionizing temperatures and cooling rates. In such a way, the respective volume fraction of each phase and both the size and the chemistry of the quenched martensite are taken as microstructural variables to decompose the peculiar work hardenability of dual-phase Ti-6Al-4V alloys into respective contributions. Then, annealing of the metastable a + a’ phases was performed for different annealing temperatures and times to bring about the a’ martensite decomposition involving a ‘partitioning’ of the alloying elements.The quenching and partitioning parameters led to a very wide range of mechanical properties and associated work-hardening behaviour. In order to shed some light on the behaviour of the complex martensitic phase and associated interphases, TEM was performed. The macroscopic mechanical behaviour is also discussed based on this multiscale characterization approach.