Final Flashcards
What is ionic Bonding?
Requires electron transfer Occurs between metal and non metal Large difference in electronegativity required Nondirectional Example: NaCl
What is covalent bonding?
Dominate bonding between non-metal atoms Involves Electron sharing Similar electronegatives Highly Directional example: CH4
What is metallic bonding?
Dominate bonding between metal atoms Share electrons Valence electrons are only loosely held by their parent nucleus Nondirectional Example: Any metals
What is a material with the least crystalline structure, highest degree of covalent bonding, and has the lowest density?
Polymers
What material exhibits ionic bonding, is a compound of metals and nonmetals, has the highest melting point
ceramics
In an interstitial solid solution, the solute atoms occupy
the interstitial sites
Grain boundaries are
two dimensional defects
Interstitials are
point defects
Two types of dislocations are
edge and screw
Degree of crystallinity for a polymer is not determined by
none of the above
The discrepancy between the theoretical and practical stress is explained by the concept of
dislocation
Why is interstitial diffusion normally more rapid than vacancy diffusion?
The interstitial atoms are smaller and are more mobile, and there are more empty interstitial positions than vacancies
Explain why it is important to keep operational temperature of a material above its DBTT
Ductile fracture is preferred
In Aluminum, self-diffusion:
atoms of aluminum will migrate through the aluminum
The maximum attainable stress for a metal is called:
Ultimate tensile stress
