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The effect of grain size on the yielding behavior of very low carbon steel

Citation

Russell, Thomas L. (1958) The effect of grain size on the yielding behavior of very low carbon steel. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechETD:etd-01232006-153919

Abstract

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This thesis presents the results of an experimental investigation of the effect of grain size on the yielding behavior of very low-carbon steel. Steel specimens of five grain sizes were produced for testing. The average grain diameter of these specimens ranged from 1.1 x 10(-3) in. to 8.1 x 10(-3) in. Two types of tensile tests were performed, one by the application of very low loading rates and the other by the rapid application of a constant stress. Both types of tests were performed at temperatures of 72°F and -320°F, while a few rapid loading tests were performed at a temperature of -109°F.

Both the static upper and lower yield points are observed to increase linearly with [...], where d equals the average grain diameter. Delay time and pre-yield micro strain for specimens that exhibited a yield point were determined from the rapid loading tests conducted at room temperature. Delay time decreases with increasing grain diameter for a given stress.

The experimental results are compared with several dislocation models for yielding. These models are shown to be incapable of describing the experimental results of this investigation. A more detailed model, based on Cottrell's yielding mechanism, is described.

Plastic deformation by twinning occurred in both static and rapid loading tests performed at a temperature of -320°F. A critical stress for twinning was observed. This stress is independent of stress rate in the range from [...] to [...]. The critical twinning stress increases linearly with [...]. The existence of a critical stress for twinning is shown to be compatible with Cottrell and Bilby's theory for the formation of twin bands.

Item Type:Thesis (Dissertation (Ph.D.))
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Mechanical Engineering
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Wood, David Shotwell (advisor)
  • Clark, Donald S. (advisor)
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 January 1958
Record Number:CaltechETD:etd-01232006-153919
Persistent URL:http://resolver.caltech.edu/CaltechETD:etd-01232006-153919
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:293
Collection:CaltechTHESIS
Deposited By: Imported from ETD-db
Deposited On:24 Jan 2006
Last Modified:26 Dec 2012 02:28

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