MAT E202 Lecture Notes - Lecture 1: Ductility, Shear Stress, Covalent Bond

• School: University of Alberta
• Department: Materials Engineering
• Course: MAT E202
• Professor: Thomas Etsell

Document Summary

Fcc a = (cid:2872)r (cid:2870: coordination # (cn) = 6, abcabc packing, has no endurance limit, cannot be cold worked that much as there isn"t much room for dislocations to form, has a close packed plane. But because of the more slip systems is more ductile than hcp: becomes very ductile at high temperatures. Has a dbtt: has an endurance limit as strain increases hardness significantly. Hcp a = 2r: cn = 12, h = 1. 63a, vc = 6r(cid:2870) (cid:885) Is close packed: has only three slip systems, as a result is the least ductile of the three structures, has abab stacking of planes. In terms of ductility fcc > bcc > hcp. Interstitial sites: tetrahedral (cid:1857)(cid:1866)(cid:1857)(cid:1870)(cid:1853)(cid:1864) (cid:1858)(cid:1867)(cid:1870)(cid:1865)(cid:1873)(cid:1864)(cid:1853)=(cid:4666)(cid:1872)(cid:1870)(cid:1853)(cid:1866)(cid:1859)(cid:1864)(cid:1857) (cid:1854)(cid:1853)(cid:1871)(cid:1857) (cid:1864)(cid:1857)(cid:1866)(cid:1859)(cid:1872) (cid:4667)(cid:2870)+(cid:4666) (cid:1853)(cid:1864)(cid:1858) (cid:1855)(cid:1857)(cid:1864)(cid:1864) (cid:1857)(cid:1859) (cid:1872)(cid:4667)(cid:2870)=(cid:4666)(cid:884)+(cid:884)(cid:1870)(cid:4667)(cid:2870, the triangle mentioned is the triangle between the two base atoms of the tetrahedral triangle. I. e. (cid:306)max = (cid:305)cos( )cos( ) when and are both 45 .