MTL 200 Lecture 3: Chapter 3

• School: Ryerson University
• Department: Mechanical Engineering
• Course: MTL 200
• Professor: Ahmad Varvani- Farahani

Document Summary

Crystal structure: the manner in which atoms (ions or molecules) are arranged in space defined according to a unit cell for example building blocks. Lattice: a regular periodic arrangement of points in crystal structures. A basic structural unit of a crystal structure, defined in terms of geometry and atom positions within a parallelepiped volume. For example copper, aluminum, silver, nickel, lead and etc. Relationship between the unit cell edge lengths aka lattice parameter (a) and the atomic radius (r) Coordination number: the number of nearest neighbor atoms. Atomic packing factor (apf): the fraction of hard sphere volume in a unit cell. (important) For example cr, fe, li, mo, nb, w, v, and etc. For example co, mg, ti, zn, zr, and etc. For hcp: 6 atoms in the unit cell, a =2r , c/a = 1. 633 (idea value) (note: c is the height, coordination number = 12, apf = 0. 74.