May i know is structure such as bcc, fcc depends on how it process?

aiklone1314

i study from some books that the properties of a materials depends on the structure of it, while the structure depends on how it being process..may i know what structure actually it means? i cant get its meaning..does it means the processing methods will influnce whether the materials will be in bcc or fcc structure? or the imperfection of crystal structure? i am quite confused with it..

Mapes

Surface roughness, grain size and precipitate size (in metals), and degree of crosslinking (in polymers) are all examples of processing-dependent characteristics that affect behavior.

aiklone1314

then may i know does process affect the material to becomes sc, hcp,bcc or fcc structure?
does sc, hcp, bcc or fcc structure exist itself in the natural or it depends on the proccesing part?

Mapes

It can depend on processing, such as when a material is cooled rapidly to a temperature where the existing phase is unstable, but transformation to the stable phase is very slow. One can even make amorphous metals this way. Another possibility is to include additives that stabilize a certain crystal structure, but I wouldn't classify this as processing as much as alloying.

Astronuc

Metals have inherent crystal structure. Some of fcc or bcc and others are hcp. That is a property of the element. Alloys are more complex, but usually take the crystal structure of the predominant element. Some alloys can take two forms based on processing.

Grain size is affected by cooling rate from liquid. The more rapid the quench, the finer the grain size. Solid materials can be hot or cold worked, which causes the formation of dislocations, lines of defects in the crystal, which when the metal is annealed form new grain boundaries.

Surface finish/roughness affects the interactions with environment. A rougher surface offers more surface area for chemical interaction, e.g., corrosion, or mechanical affects, e.g. friction.