What is the main difference between hot and cold deformation? Why annealing is applied to cold worked metals? Please explain the annealing steps.

The hypothetical binary phase diagram is given below. According to this diagram, determine the which material or materials with given compositions are age$-$hardenable and explain your answer in detail. Also, write why age hardening cannot be applied in other compositions.

Please explain the "strain hardening" mechanism by using stress$-$strain diagram. Do you think this mechanism could be used at high temperatures or not?

a$)$ What is the difference between homogeneous and heterogeneous nucleation?

b$)$ How does cooling rate affect the microstructure? Explain.

$A{l}_2{O}_3$ and $C{r}_2{O}_3$ display unlimited $($complete$)$ solid solubility.

a$)$ Draw a hypothetical binary phase diagram for $A{l}_2{O}_3-C{r}_2{O}_3$ system, and label the curves, regions, etc. $($Melting temperatures of $A{l}_2{O}_3$ and $C{r}_2{O}_3$ are $2045C$ and $2275C,$ respectively$).$

b$)$ Which requirements should be satisfied to obtain a complete solid solubility?

Mg$-20$ wt$\%Sn$ alloy is cooled from $700C.$ By drawing the diagram on your paper, For this alloy,

a$)$ Determine the starting temperature of solidification.

b$)$ Determine the composition and amount of each phase at $400C.$

a$)$ How can you explain the term of age hardening process? Please explain stages and give detailed information by giving an example.

b$)$ What is the difference between precipitation and dispersion strengthened alloys?

Explain why, under some circumstances, it is not advisable to weld a structure that is fabricated with a $3003$ aluminum alloy. Hint: strengthening of a $3003$ alloy is accomplished by cold working.

Using the isothermal transformation curve shown to the right for the Fe$-$C system, determine the final structure of the Fe$-$C alloy for the following cooling processes $($assume all processes start as homogeneous austenite above $760C)$:

a$)$ Rapidly cool to $600C,$ hold for ${10}^2$ second, rapidly cool to room temperature;

b$)$ Rapidly cool to $350C,$ hold for ${10}^2$ seconds, rapidly cool to room temperature;

c$)$ Rapidly cool to $300C,$ hold for $10$ seconds, rapidly cool to room temperature.