Material Science Midterm 1

Components of MSE Paradigm

processing, structure, properties, performance lead to characterization

three types of processing

thermal, chemical, physical

processing controls

structure

structure dictates…

properties

properties affect

performance

scales

nuclear, atomic, nano, micro, macro

traditional classes of materials

metals, ceramics, polymers and plastics, molecular solids, composite

electronegativity difference for 50% ionic

1.7 (>:ionic, <:covalent)

is attractive force negative or positive

negativei

is repulsive force negative or positive

positive

How to calculate shielding charge using slater’s rules

same shell: x0.35, (n-1) shell electrons: x0.85, (n-2) or lower: x1

important because it includes the electrons in the same shell

electronegativity increases in what direction on periodic table

right

atomic radius increases in what direction on the periodic table

left

what is the force at equilibrium

0

7 lattice systems

cubic, tetragonal, orthorhombic, hexagonal, rhombohedral, monoclinic, triclinic

cubic side lengths

equal

cubic angles

all equal 90

cubic symmetry

4 three fold

cubic bravis lattice

primitive, body center, face centered

hexagonal side lengths

two same, one different

hexagonal angles

two are 90 and other is 120

tetragonal side length

two are the same one is different

hexagonal symmetry

1 six-fold

hexagonal bravais lattice

primitive

tetragonal symmetry

1 four fold

tetragonal bravais lattice

primitive, body centered

orthorhombic side lengths

none are equal

orthorhombic angles

all 90 degrees

orthorhombic symmetry

3 two fold

orthorhombic bravais lattice

primitive, body center, face center, base centered

atomic packing factor

(# of atoms * (4/3 π³))/(cube volume)

crystal density

(# of atoms)*(atomic mass)/(volume of cube)*(avogadros number)

FCC stacking sequence

ABC

HCP stacking sequence

AB

single crystal meaning

perfect arrangement

amorphous meaning

no form, no order

monocrystalline

single crystal, complete order

polycrystalline

short range order, some long-range order