Review! - Review Session (Exam #2) MATSE 259 Review Session...

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

View Full Document Right Arrow Icon
Review Session (Exam #2) MATSE 259 Review Session (Exam #2) Slide 1
Background image of page 1

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

View Full DocumentRight Arrow Icon
Exam #2 Wednesday, October 13 6:30 PM to 7:45 PM 158 Willard (Last Names A through H) 160 Willard (Last Names I through Q 160 Willard (Last Names I through Q) 162 Willard (Last Names R through Z) MATSE 259 Review Session (Exam #2) Slide 2
Background image of page 2
Topics Covered by Exam Diffusion Strengthening Mechanisms Failure Mechanisms-Fracture Failure Mechanisms-Fatigue Failure Mechanisms-Creep Failure Mechanisms Creep Readings Callister, Materials Science and Engineering: An Introduction MATSE 259 Review Session (Exam #2) Slide 3 Chapter 5 Chapter 7 Chapter 8
Background image of page 3

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

View Full DocumentRight Arrow Icon
Diffusion MATSE 259 Review Session (Exam #2) Slide 4
Background image of page 4
Important Terminology Interdiffusion Vacancy Diffusion Self-Diffusion Interstitial Diffusion Steady-State Diffusion (Fick’s First Law) Non-Steady State Diffusion (Fick’s Second Law) Carburization MATSE 259 Review Session (Exam #2) Slide 5
Background image of page 5

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

View Full DocumentRight Arrow Icon
In steady state diffusion, diffusion flux does not change with time. Steady State Diffusion Gaseous Diffusion through a Metal Plate MATSE 259 Review Session (Exam #2) Slide 6 B A B A x x C C = Δ Δ = x C gradient ion Concentrat
Background image of page 6
Fick’s First Law dC D J = D = Diffusion coefficient (m 2 /sec) dx dC Negative sign indicates that the direction of diffusion is down the concentration gradient from a high to a low concentration. dx = concentration gradient MATSE 259 Review Session (Exam #2) Slide 7 For steady state diffusion, the concentration gradient is the driving force.
Background image of page 7

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

View Full DocumentRight Arrow Icon
Non-Steady State Diffusion Diffusion flux and the concentration gradient at a point in a solid vary with time, with a net accumulation or depletion of diffusing species resulting. Example: Ni coating Cu x MATSE 259 Review Session (Exam #2) Slide 8
Background image of page 8
C C Fick’s Second Law Under non-steady state conditions, Fick’s first law is not applicable: = x D x t 2 C D C (Fick’s second law) 2 x t = Solutions to this expression (both position and time) are possible only when physically meaningful boundary conditions are specified MATSE 259 Review Session (Exam #2) Slide 9 only when physically meaningful boundary conditions are specified.
Background image of page 9

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

View Full DocumentRight Arrow Icon
Solution for a Semi-Infinite Solid with a Constant Surface Concentration Source of diffusing species is a gas phase and the partial pressure is held constant. 1. For t = 0, C = C 0 at 0 x 2. For t > 0, C = C s at x = 0 (constant surface concentration) 3. C = C 0 at x = Boundary Conditions : = Dt x erf C C C C s x 2 1 0 0 MATSE 259 Review Session (Exam #2) Slide 10
Background image of page 10
Effect of Changes in Temperature on the Diffusion Coefficient Diffusion Coefficient for Mg in Al at 550ºC : D (T) = D o e -Q/RT ( ) + × = K 273 550 K - J/mo 314 8 J/mol 131000 exp / m 10 2 . 1 2 4 s D MATSE 259 Review Session (Exam #2) Slide 11 ( )( ) J/mol .
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.

Page1 / 59

Review! - Review Session (Exam #2) MATSE 259 Review Session...

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