Engineering Science 1021A/B Lecture Notes - Lecture 19: Work Hardening, Ultimate Tensile Strength
17 May 2018
School
Department
Professor
Cold Work / Strain Hardening
Strain hardening: process of making a metal stronger by plastically deforming it
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Consider a load-elongation curve for an annealed metal
Loading to any point on the curve followed by unloading results in elastic
recovery
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Reloading retraces the unloading curve and then resumes from the
original point of unloading
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Increased the yield strength
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Plastic deformation increases the length and decreases the cross-sectional
area
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Percent cold work: degree of plastic deformation
𝐴": initial area of the deforming section
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𝐴#: final area of the deforming section
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Strain hardening causes an increase in yield strength and tensile strength•
Strain hardening causes an decrease in Ductility•
Strain Hardening Mechanism
In order to increase the strength of a ductile metal, you must make it more
difficult for dislocations to move
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The strain hardening process accomplishes this by increasing the density of
dislocations in the metal which causes them to interact with each other
Frank-Read Source
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Strengthening in Metals
Wednesday, October 18, 2017
8:37 AM
