The influence of the initial morphology on the microstructural evolution of as cast TiNi alloys has been studied as a function of partial melting during isothermal holding at two temperatures. Results show that the globularisation of the solid phase develops preferentially in the equiaxed zone of the initial microstructure consisting of a columnar zone, a transition zone, and an equiaxed zone. As the holding time is increased the liquid fraction decreases in the equiaxed zone resulting in an increase in the size of globules and a decrease in their number. A starting microstructure consisting of refined equiaxed grains is recommended for thixoforming of TiNi alloys.
