Lecture13 - Strengthening Mechanisms point defects - solid...

Info iconThis preview shows pages 1–12. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter 8 - 1 Strengthening Mechanisms point defects - solid solution strengthening, alloying lattice strains of impurities interact with dislocation movement ex: Sterling Silver, C in Fe Steel (desks in room) other dislocations - strain hardening, cold working material becomes harder and stronger with plastic deformation due to accumulation of dislocations ex: Blacksmithing, rolling (other people in the room) grain boundaries - grain refining smaller grains -> greater total grain boundary area (processing) ex: nanocrystalline materials, rapid solidification (walls) volume obstacles - precipitation hardening, multiphase alloys dislocations cut through or go around large obstacles
Background image of page 1

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

View Full DocumentRight Arrow Icon
Chapter 8 - 2 T R Adapted from Fig. 7.22, Callister 7e. º º T R = recrystallization temperature
Background image of page 2
Chapter 8 - 3 Dislocations are observed primarily in metals and alloys. Strength is increased by making dislocation motion difficult. Particular ways to increase strength are to: --decrease grain size -- solid solution strengthening -- precipitate strengthening -- cold work Heating ( annealing ) can reduce dislocation density and increase grain size. This decreases the strength. Summary
Background image of page 3

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

View Full DocumentRight Arrow Icon
Chapter 8 - 4
Background image of page 4
Chapter 8 - 5 August 17, 1999 earthquake in northwestern region of Turkey
Background image of page 5

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

View Full DocumentRight Arrow Icon
Chapter 8 - 6
Background image of page 6
Chapter 8 - 7
Background image of page 7

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

View Full DocumentRight Arrow Icon
Chapter 8 - 8 Titanic
Background image of page 8
Chapter 8 - 9 ISSUES TO ADDRESS. .. How do flaws in a material initiate failure? How is fracture resistance quantified; how do different material classes compare? How do we estimate the stress to fracture? How do loading rate, loading history, and temperature affect the failure stress? Ship-cyclic loading from waves. Computer chip-cyclic thermal loading. Hip implant-cyclic loading from walking. Adapted from Fig. 22.30(b), Callister 7e. (Fig. 22.30(b) is courtesy of National Semiconductor Corporation.) Adapted from Fig. 22.26(b), Callister 7e. Chapter 8: Mechanical Failure Adapted from chapter-opening photograph, Chapter 8, Callister 7e. (by Neil Boenzi, The New York Times .)
Background image of page 9

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

View Full DocumentRight Arrow Icon
Chapter 8 - 10 Fracture mechanisms • Ductile fracture – Occurs with plastic deformation • Brittle fracture – Little or no plastic deformation – Catastrophic
Background image of page 10
Chapter 8 - 11 Ductile vs Brittle Failure
Background image of page 11

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

View Full DocumentRight Arrow Icon
Image of page 12
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 11/25/2008 for the course MATSCI 104 taught by Professor Lan during the Spring '08 term at UCLA.

Page1 / 27

Lecture13 - Strengthening Mechanisms point defects - solid...

This preview shows document pages 1 - 12. Sign up to view the full document.

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