Citation
Wright, William Vale (1955) Precipitation Embrittlement Studies in Vacuum Melted Iron-Chromium Alloys. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/007T-MG19. https://resolver.caltech.edu/CaltechETD:etd-01272004-092755
Abstract
This thesis presents the results of an experimental study on the nature of precipitation embrittlement (475[degrees]C embrittlement) in iron-chromium alloys. Electrical resistance, hardness, tension properties, and microstructure were studied using 19, 25, 34, 42, and 49 per cent chromium-iron vacuum melted alloys. Precipitation embrittlement was found to occur from 450[degrees]C to about 540[degrees]C with the rate of embrittlement increasing with teiriperature. Maximum embrittlement occurs near 500[degrees]C. Increasing the chromium content from 19 to 49 per cent increases the rate and magnitude of precipitation embrittlement. An activation energy of 60,000 cal/mol was established for the process. Precipitation embrittlement was found to be analogous to precipitation hardening in alloys where the formation of a coherent precipitate is responsible for property changes in the alloy. A chromium rich body centered cubic ferrite with slightly larger lattice parameter than the iron rich matrix is proposed as the non-equilibrium coherent precipitate which eventually decomposes to form gross sigma phase.
Item Type: | Thesis (Dissertation (Ph.D.)) |
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Subject Keywords: | (Mechanical Engineering and Physics) |
Degree Grantor: | California Institute of Technology |
Division: | Engineering and Applied Science |
Major Option: | Mechanical Engineering |
Minor Option: | Physics |
Thesis Availability: | Public (worldwide access) |
Research Advisor(s): |
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Thesis Committee: |
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Defense Date: | 1 January 1955 |
Record Number: | CaltechETD:etd-01272004-092755 |
Persistent URL: | https://resolver.caltech.edu/CaltechETD:etd-01272004-092755 |
DOI: | 10.7907/007T-MG19 |
Default Usage Policy: | No commercial reproduction, distribution, display or performance rights in this work are provided. |
ID Code: | 366 |
Collection: | CaltechTHESIS |
Deposited By: | Imported from ETD-db |
Deposited On: | 29 Jan 2004 |
Last Modified: | 07 Jul 2023 00:02 |
Thesis Files
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PDF (Wright_wv_1955.pdf)
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