PLASTIC DEFORMATION
What are dislocations?
Dislocations are line defects that exist in
metals
There are two types of dislocations:
edge and screw
The symbol for a dislocation is
The dislocation density in annealed
metals is normally r = 106/cm2
Slip
Dislocations move on a certain
crystallographic plane: slip plane
Dislocations move in a certain
crystallographic direction: slip direction
The combination of slip direction and
slip plane is called a slip system
Positive-positive dislocation interaction
Results in more stress to move
dislocations (or cause plastic
Shear band formation
Limited non-homogeneous deformation
Very large localized strain e~1 or 100%
Occurs especially under high strain
rates
Mechanism of deformation still unclear
deformation):called work hardening
This type of interaction also leads to
dislocation multiplication which leads to
more interactions and more work
hardening
Twinning
Common in hcp and bcc structures
Limited deformation but help in plastic
deformation in hcp and bcc crystals
Occurs on specific twinning planes and
twinning directions
المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .
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