1. Why did it take society so long to develop metals?
2. Define an alloy.
3. Why do metals break even though they are not stressed beyond their elastic limit? What conditions cause this type of failure?
4. What would be the advantage of alloys that would withstand higher temperatures?
5. Why does recycling save so much energy?
6. Removing elemental metal from its ore is called._______
7. What impact does quenching have on ferrous metals?
8. What effect on tensile strength does stretching copper have?
9. Does rusting of steel occur at the anode of cathode?
10. What material is used as a "sacrificial" anode of steel?
11. What metal is alloyed with iron to make stainless steel?
12. What mechanical process is accomplished by stretching copper?
13. What happens to dislocations when a wire is bent?
14. Give the words for the following acronyms: FCC, BCC, HCP.
15. How does the metal composition differ in a paper clip and a bobby pin?
16. Compare the grain differences in normal steel and quenched steel.
1. Why did it take society so long to develop metals. It is very difficult to form elemental metals from their ores. It often requires very high temperatures. The technology for this process took many years to develop.
2. Define an alloy. A substance that has metallic properties and is made up of two or more chemical elements, of which at least one is a metal. The two types of alloys are in
3. Why do metals break even though they are not stressed beyond their elastic limit? What conditions cause this type of failure? Under repetitive stresses, cracks in a metal can develop and grow.
4. What would be the advantage of alloys that would withstand higher temperatures? They could be used for many applications, such as higher temperature gasoline engines, nuclear reactor containment vessels, etc.
5. Why does recycling save so much energy? Because of the large amount of energy required to form elemental metals from their ores.
6. Removing elemental metal from its ore is called Extracting or Reduction .
7. What impact does quenching have on ferrous metals? If the metal contains carbon, the carbon will not be able to separate during the FCC to BCC transition and will be trapped, resulting in a distorted BCC structure. This hard, brittle form of steel is called Martensite.
8. What effect on tensile strength does stretching copper have? Stretching copper increases its tensile strength due to the formation of dislocations which become pinned.
9. Does rusting of steel occur at the anode of cathode? Rusting is an oxidation process and occurs at the anode.
10. What material is used as a "sacrificial" anode of steel? Zinc is used in galvanized steel.
11. What metal is alloyed with iron to make stainless steel? Chromium.
12. What mechanical process is accomplished by stretching copper? Cold-working.
13. What happens to dislocations when a wire is bent? More dislocations form and they get tangled or pinned.
14. Give the words for the following acronyms: FCC, BCC, HCP. FCC - Face centered cubic, BCC - Body centered cubic, HCP - hexagonal closest packed
15. How does the metal composition differ in a paper clip and a bobby pin? The bobby pin contains more carbon and is harder and stronger.
16. Compare the grain differences in normal steel and quenched steel. Normal steel contains separate grains of BCC arranged Fe and Fe3C. In quenched steel, the carbon remains in the BCC iron crystals distorting its structure.