(i) Using the Al-Si phase diagram, calculate the amount of liquid existing just above the eutectic temperature for an alloy containing x = 0.3 mole fraction of silicon. You may assume that density effects can be neglected and that aluminium has a zero solubility in silicon. The eutectic composition is indicated as xsi=0.12. [30%] 1400 L Temperature /°C 1100 800 L+Als Als 500 ←si = 0.12 Als +Siss T L+Sig 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 ΑΙ ← !Sx Si Si (ii) Describe the microstructure obtained in this alloy as it is cooled below the eutectic temperature. Mention the fractions of eutectic and pro-eutectic phases. [10%] (iii) Al-Si alloys of eutectic composition are used extensively to make large engine-blocks for internal combustion engines. Give two reasons why this is the case. (iv) Describe three kinds of information that can be obtained from a phase diagram. [30%] [30%]