An alloy X with a composition of A $?70$ ?wt $\%$ ?B is cooled from a temperature of $900\backslash$deg C to room temperature. List the phase transformation sequence the alloy undergoes. Indicate clearly what transforms into what. Sketch the microstructure at room temperature and label the features of the sketch. Immediately after the eutectic reaction, what percentage of the microstructure of X consists of the eutectic mixture?

T (C) 800 500 A a 10 30 L 90 b B 600