PHASE TRANSFORMATION MECHANISMS IN BORON ALLOYED TI‐6AL‐4V WELD STUDIED USING BETA GRAIN RECONSTRUCTION

Paper i proceeding, 2024

Substantial effort is put on decreasing the size of both β grains and α colonies of cast, additively manufactured and welded titanium alloys.
To evaluate the effect of these efforts, effective methods to characterize the size and orientation of β grains over relatively large regions
are needed. In the present work the microstructure of a laser weld in cast Ti‐6Al‐4V alloy with 0.11 wt.% boron has been studied. Electron
back scatter diffraction technique was used to capture a low magnification orientation map of the alpha phase across different weld zones.
A method of prior β grain reconstruction based on Burgers orientation relationship was applied to study the prior β grain structure in the
different weld zones. The prior β grain reconstruction could be performed successfully and the reliability of the reconstruction was
evaluated. The fine microstructure in the weld zones together with low magnification resulted in a relatively low indexing rate in the
fusion zone and heat affected zone but this did not affect the quality of prior β grain reconstruction. Analysis of the variant selection and
orientation deviation in the reconstructed β grains can give information about the transformation mechanisms in the different weld zones.