University of Surrey

Test tubes in the lab Research in the ATI Dance Research

The flow stress of Invar alloys.

Ebrahimi, F. (1976) The flow stress of Invar alloys. Doctoral thesis, University of Surrey (United Kingdom)..

Available under License Creative Commons Attribution Non-commercial Share Alike.

Download (6MB) | Preview


Iron-nickel Invar alloys containing 30-40% Nickel have an unusually large temperature dependence of the flow stress (0.15 Kg/mm[2].[o]K), completely untypical of FCC metals. This behaviour is reported to disappear as the temperature approaches the Curie temperature of these alloys and the present work comprises both practical and theoretical justification of these previously reported results. The effect of grain size on the temperature dependence of the flow stress for the above mentioned alloys has also been investigated and no significant effect has been observed. A new theoretical approach has been made, which examines interactions between dislocations and magnetization by combining the theories of Weiss and Yamamoto and his co-workers. On the basis of this analysis, specific binary and ternary alloy composition has been selected and tested to allow verification of the developed theory. A number of predictions of the combined theory have been examined, and a good agreement with the experiments has been observed in most cases, although some predictions have not received experimental confirmation. This leads to the conclusion that the Weiss theory may have to be modified to some extent, but the present work substantiates a basically magnetic origin for the mechanical abnormalities in Invar alloys.

Item Type: Thesis (Doctoral)
Divisions : Theses
Authors :
Ebrahimi, F.
Date : 1976
Contributors :
Additional Information : Thesis (M.Phil.)--University of Surrey (United Kingdom), 1976.
Depositing User : EPrints Services
Date Deposited : 22 Jun 2018 13:00
Last Modified : 06 Nov 2018 16:52

Actions (login required)

View Item View Item


Downloads per month over past year

Information about this web site

© The University of Surrey, Guildford, Surrey, GU2 7XH, United Kingdom.
+44 (0)1483 300800