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
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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)|
|Defense Date:||1 January 1958|
|Default Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Imported from ETD-db|
|Deposited On:||24 Jan 2006|
|Last Modified:||26 Dec 2012 02:28|
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