Material Science Flashcards
What is Ionic Bond?
Where one or more electrons from an atom transfers to another due to the opposite polarity of the charge holds the element together.
What is Covalent Bond?
the bond formed by shared electrons
What is Metallic Bond?
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.
What is Molecular Bond?
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.
What is Hydrogen Bond?
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.
List the three lattice type structures that occur in metals.
- Body-Centered Cubic. (BCC).
- Face-Centered Cubic. (FCC).
- Hexagonal Close-Packing. (HCP).
Describe the various imperfections that occur in solid materials.
- Point Imperfections.
- Line Imperfections.
- Edge Dislocations.
- Screw Dislocations.
- Mixed Dislocations.
- Macroscopic (Bulk) Material Defects.
What are common characteristics of Alloys?
- Stronger than pure metals.
- Reduced thermal and electrical conductivity.
What is Strength?
the ability of a material to resist deformation. The maximum load that can be borne before failure occurs.
What is Ultimate Tensile Strength?
The maximum resistance a material presents to fracture.
What is Yield Strength?
the stress where plastic deformation starts.
What is Ductility?
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.
What is Malleability?
Is the ability to exhibit large deformation or plastic response when sujected to compressive force
What is toughness?
the way a material reacts under sudden impacts.
What is Hardness?
the property of a material enabling its resistance to plastic deformation, penetration, indentation, and scatching.
What is Heat Treatment?
The process of heating a metal then cooling (quenching) it will cause the metal to become harder.
What is Quenhing?
Cooling the metal after heating it up. by varying the rate that you cool the metal varies the levels of hardness and tensile strength.
What is Annealing?
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.
What is caused by Cold Working?
results in decreasing ductility by repeatedly deforming the metal at low temp. the metal will not re-crystalize
What is Hot Work?
the process where metal deformation occurs above the re-crystallization temperature, preventing strain hardening for occurring.
What are Three material failure mechanisms?
- Fatigue failure.
- Work hardening.
- Creep.
