Globularisation of alpha Lamellae in Titanium Alloy: Effect of Strain, Strain Path and Starting Microstructure

摘要

To gain in-depth understating on the globularisation of alpha lamellae in titanium alloys, a systematic study has been carried out to evaluate the effect of strain and strain path on the microstructural evolution of titanium alloy Ti-6Al-4V with two different starting microstructures viz., water quenched martensitic and air cooled lamellar microstructure. Ti-6A1-4V was subjected to similar amounts of strain using uniaxial (monotonic) and multi-axial (non-monotonic) deformation. A vis-A -vis comparison of the microstructures obtained after deformation revealed that the material with fine alpha lamellae exhibits better globularisation kinetics irrespective of the mode of deformation. Further alteration of the strain path (multi-axial or non-monotonic) in the material before achieving critical percentage of deformation results in reduced globularisation. Beyond this critical amount of deformation, the results obtained for both monotonic and non-monotonic deformation are comparable. However, multi-axial or non-monotonic deformation results in better homogeneity in terms of microstructural evolution.