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12. pointers. T and Composition can both be varied while still being in the single phase region. HOLZ. HOLZ. HOLZ. Solved example. The Graphene Crystal. 0 border 16 pt. Solved example. Bending of rod of metal. −ve. 0. +ve. Continued…. Text boxes. SUMMARY. 0.2 spacing.
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12 pointers T and Composition can both be varied while still being in the single phase region HOLZ HOLZ HOLZ
Solved example The Graphene Crystal 0 border 16 pt Solved example Bending of rod of metal −ve 0 +ve Continued… Text boxes SUMMARY • 0.2 spacing 0.0 spacing 16 Funda Check • 0.2 spacing Advanced Topic dkasdfl; Addition of Carbon 0.0 spacing 0.0 spacing 20 18 • 0.5 spacing 0.2 spacing Q & A Q & A 0.5 spacing 0.0 spacing 0.0 spacing 18 18 Energy 0.5 spacing 20 Q & A Symmetries Note that this is a special case- usual GBs are not like this 0.5 spacing 20 18 • 0.2 spacing Q & A Solved Example The Graphene Crystal Lattices SP Symmetries 20 12 D .1 borders 20 pt Attractive Repulsive D SUMMARY 14 M Fraunhofer 1 20 dlf Important Note dlf 16 d 12 1 10 20 18 Click here C A T > 18 Click here Click here to know more about [1] BCC 2 A kkk r0 Click here to know more about Red 1 3 3 2 A Continued… Not a parallelepiped NOte Click here A C B B Peak Ahead SP Solved Example Funda Check C Lattices Solved example Lucida calligraphy
Asymmetric Unit 40 33 Bonding and Elastic modulus Watch Video 40 30 22 SEM Click here to know more Asymmetric Unit More views Text boxes More views A B 18 C 20 18 Text boxes 18 12 Asymmetric Unit Asymmetric Unit The SYMMETRY ref 10 Intergranular Glassy Films Times 20 12 SEM Unit cell 20 Times 20 Times 16 Times 18 Times 16 The Turnbull’s SEM .2 .1 .2 12 Schematics ss Unit cell SYMMETRY 20 .2 .1 .2 ss Symmetry 20 very light blue 22 18 0000 margins SYMMETRY CONCLUSIONS 22 20 SYMMETRY SEM ss 22 cc + Times 16 SYMMETRY 30 Video: sfdlk 20 Click here to know more Graphics: Continued… * Back E-book Watch Video http://home.iitk.ac.in/~anandh/E-book.htm
Funda Check • Why do we need 3 indices (say for direction) in 3-dimensions? 22 • 20 20 • 18 20 Important points to be noted: • The x-axis is log scale. ‘Nose’ of the ‘C’ curve is in ~sec and just below TE transformation times may be ~day. • The ( + Fe3C) phase field has more labels included. • There are horizontal lines labeled Ms and Mf. • 18 18 • 18 18 18 •
20 • 18
Solved Example
Other relevant topics m More views • Why do we need 3 indices (say for direction) in 3-dimensions? Q & A Jump Quantum How are atoms assembed to form a nucleus of r* “Statistical Random Fluctuation” m Quantum Jump A
20 • 18 • • 20 • 18
Note: OVERVIEW SLIDE (don’t try to understand everything in this slide!)
Equations • → shear modulus of the crystal • w → width of the dislocation !!! • b → |b|
Asymmetric Unit Circles/curves Anchor circles Square with corner locks + Translation a
Trees Bonding Intra-molecular Inter-molecular Material Properties PN stress, strain rate sensitivity Factors which affect ductility Testing conditions COVALENT COVALENT T, crosshead velocity Geometry/state of stress IONIC IONIC T, crosshead velocity METALLIC METALLIC
Phase contrast ~ Fringes Phase contrast ~ Fringes Thickness Fringes Thickness Fringes Bend contours Bend contours Fresnel Fringes Bend contours Moiré patterns Moiré patterns Lattice fringe Imaging Lattice fringe Imaging Absorption contrast Nothing more Mass-thickness contrast small effect in a thin specimen Amplitude Contrast Diffraction contrast Bright Field & Dark Field Images
Phase Object approximation Phase change = f(Vt) Maximum Principal Stress Rankine/Coulomb Weak Phase Object approx. Stress based Maximum Shear Stress Tresca Yield Criteria Strain Based Maximum Principal Strain St. Venant Maximum Strain Energy Density Haigh Beltami Energy Based Maximum Distortion Energy Density von Mises
Elastic Long range(T insensitive) Modulus Long range order Solute-dislocation interaction Stacking fault Short range(T sensitive) Electrical Short range order
Thermodynamics Classification of Phase Transformations Based on Mechanism Kinetics A Heat (to 550oC) → solid solution supersaturated solution B Quench (to RT) → Increased vacancy concentration C Age (reheat to 200oC) → fine precipitates
Equations Point groups
Warm working Warmg Van der Walls forces Warm working Warm working Or a Void sizes are for Fe Grain boundary region Grain boundary region
Extremesituations Distance markers ↑ t
j d
Text boxes Frank-Read dislocation source→ • Solidification from the melt • ► Heterogeneous nucleation at second phase particles ► During phase transformation
Scanning Electron Microscopy • I I D O, (). Recommended website
Solved Example Data for Cu: • Hf (Cu vacancy) = 120 103 J/mole • R (Gas constant) = 8.314 J/mole/K
C [0001]
Graphs +2 Cs = 1 mm, E0 = 200 keV, f = 58 nm) → T(u) = 2 Sin()→ 4 2 6 T (K) → 2.5Å Stress → 2 u (nm1)→ strain →
→ →
Elastic strains → → → → 2 2
4 5 6 7 8
4 5 6 7 8
[1] Probe diameter→ Probe current→ Graphite → → → Diamond 320 300 310 280 290 → Energy-loss (eV) → Tensile → →
Slip plane normal Slip direction A
CRSS Increase→ Particle radius (r)→
36000 25 kV 5 kV • Specimen: Evaporated Au particles • Accelerating voltage Better image sharpness Improved resolution
How does the motion of dislocations lead to a macroscopic shape change? (From microscopic slip to macroscopic deformation a first feel!) Step formed when dislocationleaves the crystal Dislocation formed bypushing ina plane