The formation of α at triple junctions of parent β phase in titanium alloys

We have examined the formation of alpha phase at grain boundary triple junctions of parent beta in a metastable beta titanium alloy with orientation imaging microscopy based on electron backscattered diffraction (EBSD). As in the case of alpha formed at grain boundaries of parent beta grains, alpha at a triple junction also forms with the Burgers orientation relationship with one of the three neighbouring beta grains. The experimental results are analyzed in terms of the deviation of the 36 possible alpha variants that can form at a triple junction from the Burgers orientation relationship with neighbouring grains.