Material Science

Question 1

What is Ionic Bond?

Answer 1

Where one or more electrons from an atom transfers to another due to the opposite polarity of the charge holds the element together.

Question 2

What is Covalent Bond?

Answer 2

the bond formed by shared electrons

Question 3

What is Metallic Bond?

Answer 3

The atoms do not share or exchange electrons to bond together. Many electrons roughly one for each atom are more or less free to move thought the metal. each electron can interact with many of the fixed atoms.

Question 4

What is Molecular Bond?

Answer 4

A temporary weak charge exists when electrons of neutral atoms spend more time in one region of their orbit than in another region. The molecule weakly attracts to other molecules.

Question 5

What is Hydrogen Bond?

Answer 5

Hydrogen bond occurs because of the ease with which hydrogen atoms are willing to give up an electron to atoms of oxygen, fluorine, or nitrogen.

Question 6

List the three lattice type structures that occur in metals.

Answer 6

1. Body-Centered Cubic. (BCC).
2. Face-Centered Cubic. (FCC).
3. Hexagonal Close-Packing. (HCP).

Question 7

Describe the various imperfections that occur in solid materials.

Answer 7

• Point Imperfections.
• Line Imperfections.
• Edge Dislocations.
• Screw Dislocations.
• Mixed Dislocations.
• Macroscopic (Bulk) Material Defects.

Question 8

What are common characteristics of Alloys?

Answer 8

• Stronger than pure metals.
• Reduced thermal and electrical conductivity.

Question 9

What is Strength?

Answer 9

the ability of a material to resist deformation. The maximum load that can be borne before failure occurs.

Question 10

What is Ultimate Tensile Strength?

Answer 10

The maximum resistance a material presents to fracture.

Question 11

What is Yield Strength?

Answer 11

the stress where plastic deformation starts.

Question 12

What is Ductility?

Answer 12

The ability of a material to deform easily on the application of a tensile force. or the ability to withstand plastic deformation with out rupturing.

Question 13

What is Malleability?

Answer 13

Is the ability to exhibit large deformation or plastic response when sujected to compressive force

Question 14

What is toughness?

Answer 14

the way a material reacts under sudden impacts.

Question 15

What is Hardness?

Answer 15

the property of a material enabling its resistance to plastic deformation, penetration, indentation, and scatching.

Question 16

What is Heat Treatment?

Answer 16

The process of heating a metal then cooling (quenching) it will cause the metal to become harder.

Question 17

What is Quenhing?

Answer 17

Cooling the metal after heating it up. by varying the rate that you cool the metal varies the levels of hardness and tensile strength.

Question 18

What is Annealing?

Answer 18

another common heat treationg process for carbon steel components. slowly heating to an elevated temperature where it is held for a long time then cooled. This softens the steel and improves ductilty, relieves internal stresses caused by previous processes such as welding or machining.

Question 19

What is caused by Cold Working?

Answer 19

results in decreasing ductility by repeatedly deforming the metal at low temp. the metal will not re-crystalize

Question 20

What is Hot Work?

Answer 20

the process where metal deformation occurs above the re-crystallization temperature, preventing strain hardening for occurring.

Question 21

What are Three material failure mechanisms?

Answer 21

1. Fatigue failure.
2. Work hardening.
3. Creep.