Question

1. True or false: Cast iron and steel can be distinguished on the phase diagram by their phase transformation type

2. True or false: A stable nucleus forms when the free energy can be reduced by nuclei growing larger

3. True or false: Significant scatter in fracture strenght of a given ceramic is likely a result of the materials sensitivity to internal flaws

Answer 1

1. No there is no difference between phase transformation of steel and cast iron they only differe in carbon content steel-0.008 to 2.11% and cast iron -2.11 to 6.67%. So phase transformations before 2.11% carbon is steel and after 2.11% is cast iron. So FALSE

2. True. Increase in size of the nucleus leads to formation of stable nuclues as liquid freezes calmly and free energy at the solid phase becomes equal to liquid phase when size increases.

3. False. The internal flaws of the ceramic is due to the charge neutrality and non- stoichiometric composition and not scatter in fracture streangth.