Chapt 1 Structure - EMA4120 Physical Metallurgy I, Chapt 1...

Info iconThis preview shows pages 1–7. Sign up to view the full content.

View Full Document Right Arrow Icon
EMA4120 Physical Metallurgy I, Chapt 1 Structure of Metals University of Florida, Dept. of Materials Science and Engineering EMA4120 Physical Metallurgy I Chapter 1: Structure of Metals Paul Holloway 202 Rhines Hall 846-3330 [email protected]
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
EMA4120 Physical Metallurgy I, Chapt 1 Structure of Metals University of Florida, Dept. of Materials Science and Engineering Structure of Metals Polycrystalline Grain sizes from 10 nm to 10 cm Typically 10-100 μ m Multi-phase Microstructure and macrostructure Metallographic preparation Cut sample Mount in epoxy, metal, thermoset polymer, filler Rough grind (<320 grit) Fine grind [320 (33 μ m )-400 (23 μ m)-600 (17 μ m) SiC grit] Rough polish (diamond; typically 6 μ m) • Final polish (Al 2 O 3 , typically 0.05 μ m) Etch, electropolish
Background image of page 2
EMA4120 Physical Metallurgy I, Chapt 1 Structure of Metals University of Florida, Dept. of Materials Science and Engineering Optical Photomicrograph of 40% CW Cu-5% Zn Grains
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
EMA4120 Physical Metallurgy I, Chapt 1 Structure of Metals University of Florida, Dept. of Materials Science and Engineering The 14 Bravais lattices grouped into 7 lattice types. The restrictions on the lattice parameters (a,b,c) and the angles of the unit cell are listed for each. What are the most common ? Cubic Simple Face-centered cubic-fcc Body-centered cubic-bcc Tetragonal Simple Body-centered tetragonal Hexagonal Simple Close packed (2 atoms per point) Orthorhombic Simple Body-centered Base-centered Face-centered Rhombohedral Monoclinic Simple Base-centered Triclinic Simple Trigonal
Background image of page 4
EMA4120 Physical Metallurgy I, Chapt 1 Structure of Metals University of Florida, Dept. of Materials Science and Engineering The hard spheres or ion cores touch one another across a face diagonal the cube edge length, a= 2R 2 The coordination number, CN = the number of closest neighbors to which an atom is bonded = number of touching atoms, CN = 12 Number of atoms per unit cell, n = 4 . (For an atom that is shared with m adjacent unit cells, we only count a fraction of the atom, 1/m). In FCC unit cell we have: 6 face atoms shared by two cells: 6 x 1/2 = 3 8 corner atoms shared by eight cells: 8 x 1/8 = 1 Atomic packing factor, APF = fraction of volume occupied by hard spheres = (Sum of atomic volumes)/(Volume of cell) = 0.74 (maximum possible) 4 close packed (111) planes & 3 close packed [110] directions = 12 systems Face-Centered Cubic Crystal Structure (II) R a
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
EMA4120 Physical Metallurgy I, Chapt 1 Structure of Metals University of Florida, Dept. of Materials Science and Engineering 1/2,1/2,1/2 1/2,1/2,1/2 the 1/2,1/2,1/2 position [center of the cube] does not lie in the (111) plane (111) Planes in Cubes – Perceptions and Misperceptions (111) Planes in Cubes – Perceptions and Misperceptions (111) planes are spaced at intervals of 1/3 the body diagonal – 3 1/2 a o /3 the center of the cube lies midway between two (111) planes
Background image of page 6
Image of page 7
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 11/16/2011 for the course MSE 4120 taught by Professor Holloway during the Fall '11 term at University of Florida.

Page1 / 31

Chapt 1 Structure - EMA4120 Physical Metallurgy I, Chapt 1...

This preview shows document pages 1 - 7. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online