A 2-in. cube solidifies in $4.6 \mathrm{~min}$. Assume $n=2$. Calculate (a) the mold constant in Chvorinov's rule; and (b) the solidification time for a $0.5$ in. $\times$ $0.5$ in. $\times 6$ in. bar cast under the same conditions.

What is Sievert's Law? How can gas porosity in molten alloys be removed or minimized?

How do machines in ski resorts make snow?

Why is precipitation hardening an attractive mechanism of strengthening for aircraft materials?

What is a time-temperature-transformation diagram? How is it used?

Why does increasing the time for a heat treatment mean recrystallization will occur at a lower temperature?

Explain why a tungsten filament used in an incandescent light bulb ultimately fails

Why is it that grain growth is usually undesirable? Cite an example where grain growth is actually useful.

Explain the three stages of the annealing of metallic materials(b) For each temperature, state which stages of the annealing process occurred. Justify your answers by referring to features of the plot.

Cold working cannot be used as a strengthening mechanism for materials that are going to be subjected to high temperatures during their use. Explain why.

Thermoplastic polymers such as polyethylene show an increase in strength when subjected to stress. Explain how this strengthening occurs.

Does a strain-hardening mechanism depend upon grain size? Does it depend upon dislocation density?

What does the term “hardness of a material” mean?

What is strain hardening, and what effects does it have on the properties of metals?