Microstructural evolution in wire-drawn Ti-22Al-26Nb powder

The microstructural evolution in Ti-22Al-26Nb, as it was drawn from hot iso statically pressed powder to a 0.13 mm wire, is followed by scanning electr on microscopy (SEM) and transmission electron microscopy (TEM). The primary alpha (2) particles present in the starting powder persist throughout the drawing process, although they undergo both morphological and crystallograp hic changes. They are altered from 4 to 5-mum-diameter, equiaxed particles to 1 to 2-mum-diameter, highly elongated particles by the drawing process. In addition, these primary particles transform in situ to alpha (2) + O pha ses. There is considerable oxygen pickup during the intermediate annealing cycles, but the increased oxygen has not deleteriously affected room-temper ature tensile ductility.