DX$13$

$1.$ A $-$ B $$ A $1000$ K $$ B $1200$ K $$ A $$ B $$ A $$ B $$ eutectic $$ Eutectic $$ Xp $=0\mathrm{.}4$ eutectic $800$ K $($a$)(1)($b$)1400$ K$1100$ K$900$ K$700$ K $()($c$)$ eutectic $324($d$)$ A $0\mathrm{.}4$ A $$ B $$ eutectic $($e$)$ A $$ A $$