1. why does the metal with finer grains have not only higher strength and hardness but also higher plasticity and toughness than those of coarse grains at room temperature?
2. How should ones process the conductor made of copper wire after cold-drawing it?why?
3. The melting points of Zn,AL,and Sn are known to be 419.c,660.c and 232.c
Respectively Calculate the minimum temperatures of recrystallization of them?
4. What is the difference between a phase and a microconstituent?
5. What is carbon content of an iron-carbon alloy for which the fraction of total ferrite is 0.94?
6. Why are manganese sulphide inclusions in steel preferable to iron sulphide ones?
7. “Quality of high-carbon steel is better than that of low-carbon steel”.is right this statement?
What standard is quality (good or bad) of steel specified according to?Why?
8. (a) What is the distinction betweem hypoeutoid and hypereutectoid steels?
(b) In a hypoeutectoid steel,both eutectoid and proeutectoid ferrit exsist.Explain the difference between them.What will be the carbon concentration in each?
9. Completely label Figure :完全分类
10. Draw two isomorphous phase diagrams ,one with a large freezing range between the liquidus and solidus,the other with a small freezing range between the liquidus and solidus.In which of the two alloy systems do you expect a greater amount of segregation?Explain
11.Analyze the crystallization procrss of alloy I in figure3-18
12.Refer to Figure 3-30.If the first precipitate to be formed when an alloy is cooled has 60 percent solid B,determine the overall liquid composition.
13.Once more refer to Figure3-30.At an overall composition of 50 percent B,it is found that the liquid phase contains 40 percent B and the solid phase contains 80 percent B.Determine the percentage of the solid and the liquid present.