$(40$ pts$.$ total$)$ Using the $Ni-$ Ti phase diagram on page $6,$ if you start at point and $20wt.$

$\%Ni)$ and cool down very slowly through to $600C($point $D),$ sketch the microstructure

associated with each letter, determine what phases are present at each letter, determine the

compositions for each phase, and determine the weight in each phase. The $100$kgNi$-Ti$

mixture has $70$ wt$.\%Ni$ in it$.$ Some Ni$-$Ti alloys are so$-$called shape$-$memory alloys.

$($After Binary Alloy Phase Diagrams, ASM Int., $1986,$ p$.1768.)$

Point C $76C^{\text{M}\text{i}\text{c}\text{r}\text{o}\text{s}\text{t}\text{r}\text{u}\text{c}\text{t}\text{u}\text{r}\text{a}\text{l}\text{d}\text{r}\text{a}\text{w}\text{i}\text{n}\text{g}\text{P}\text{h}\text{a}\text{s}\text{e}(s)present}$

Weight $\%$ of $Ni$ in each phase

Weight of each phase

do it for $1700$ deggrees C$,1120$ degrees C$,635$ deegees C and $600$ degrees c