Distinct serrations had been observed on the stress-strain curves of various steels tested previously at high temperatures (950--1100°C) at McGill University. An explanation proposed for this behavior was that dynamic strain aging (DSA), caused by the presence of substitutional elements, was taking place. To investigate the possibility that the jerky flow was caused by an interaction between dislocations and substitutional elements, the conditions of temperature and strain rate under which serrated yielding had previously been observed were explored. In addition, some of the same material was utilized in the testing. / Much of the previous work on DSA in steel has focused on the effect of interstitials, namely, carbon and nitrogen, rather than that of substitutional elements. These studies have been conducted in the blue brittle region (i.e. 100--400°C), where the diffusivity of the interstitial elements is sufficiently rapid for them to keep up with the moving dislocations. However, for substitutional elements to obtain enough mobility to induce DSA, the temperature range must be significantly higher. / The effect of substitutional elements on DSA in steel was examined in torsion and, although numerous tests were formulated and carried out in an attempt to gather evidence for this phenomenon, no firm data for the occurrence of DSA were obtained. Further experiments and analysis will be required to gain a better understanding of the behavior of DSA at elevated temperatures, particularly for the case where dynamic recrystallization is taking place. A testing method might then be devised that could make the effect of DSA more evident.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.29855 |
| Date | January 1999 |
| Creators | Cunningham, Sandra, 1974- |
| Contributors | Jonas, J. J. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Engineering (Department of Mining and Metallurgical Engineering.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001737891, proquestno: MQ55019, Theses scanned by UMI/ProQuest. |
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