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
Cold working
Deformation at temperatures below 0.4
Tm
Dislocation density increases from
106/cm2 to 1010-12/cm2
High dislocation density results in a
large number of dislocation interactions
which results in high strength and
hardness
Grain size refinement
Small grains result in higher strength
Small grains is equivalent to a large
number of grain boundaries in the same
volume
Grain boundaries act as barriers to
dislocation motion
Precipitation hardening
Precipitates are second-phase particles
Hard precipitates act as barriers to
dislocation motion
Applicable only to some alloy systems
Solid solution strengthening
Interaction between stress fields of alloy
atoms and dislocations
This is the purpose of alloying
Mechanism
Strength is inversely proportional to grain size
s = s0 + kyd-1/2
Hall-Petch equation
Smaller grains have more boundary area and hence more
barriers to dislocation motion
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 .
الرجوع الى لوحة التحكم
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