Structures Flashcards
Different scales of structure in materials and examples
How can processing change properties of a material?
Change chemical composition, rate of cooling, shape, and structure
What are the different scales of structure?
Atomic, Crystal, Micro, Macro
What does atomic structure affect?
Melting point, conductivity, reflectivity, density
What are metallic bonds?
An array of ion cores in a sea of delocalised electrons
What does crystal structure affect?
Density and mechanical properties such as strength and ductility
What are three different crystalline structures?
Body centre cubic, face centre cubic, close-packed hexagonal
What crystalline structure is not ductile?
Close-packed hexagonal
What arrangement is typical of Cu, Fe, Ni and Co?
Face centre cubic
What arrangement is typical of Mg and Ti
Close-packed hexagonal
How can you make a close-packed hexagonal arranged metal more ductile?
Heat to make atom planes more mobile
What does microstructure affect?
Mechanical properties; related with phases
What is a phase?
A region of homogenous
What are the phases of steel with Fe and 0.18% C
White phase is ferrite, with 0.0012 C: is ductile but low strength; Dark pearlite is a composite of ferrite and Fe3C: Fe3C is strong, hard, brittle, and not ductile
What type of material tends to be stronger, pure or impure?
Impure
What type of material tends to be more ductile, pure or impure?
Pure