(i) Explain the circumstances in which a pure liquid might solidify with the growth of dendrites rather than by the movement of a planar liquid-solid interface. [40%] (ii) Why is it possible to obtain dendritic solidification of an alloy when the temperature increases as a function of distance ahead of the solidification front? [40%] (iii) Which of these would reduce the tendency to form dendrites? - Large solute concentration. - Low growth rate. - Large, positive temperature gradient in the liquid ahead of the solidification front. - Small partition coefficient