ENGR 220 Lecture 8 Chapter 4 All Except 4.11
Crystal Wall Gazing Reading
Substitutional Solid Solutions A. Hume-Rothery Rules 1. Difference in Atomic Radius <15% 2. Closeness in electronegativity B. Same Crystal Structure 1. FCC,BCC,HCP,SC C. Valancey 1. All else being equal 2. Metal will have a greater tendency to dissolve a metal of higher valency than one of lower valence Linear Defects A. Dislocation 1.1-D defects around which atoms are misaligned B. Two Types 1. Edge Dislocation a) Extra half-plane of atoms inserted into a crystal structure b) Wedge c) Burgers Vector Perpendicular 2. Screw Dislocation a) Spiral planar ramp b) Shear deformation c) Like a spiral parking ramp d) Burgers Vector Parallel Planar Defects A. Twin Boundary 1. Shearing 2. Mirror lattice symmetry
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