Precipitation Behavior During Thin Slab Thermomechanical Processing and Isothermal Aging of Copper-bearing Niobium-Microalloyed High Strength Structural Steels: The Effect on Mechanical Properties
We describe here the precipitation behavior of copper and fine-scale carbides during thermo-mechanical processing and isothermal aging of copper-bearing niobium-microalloyed high strength steels. During thermo-mechanical processing, precipitation of ɛ-copper occurs in polygonal ferrite and at the austenite–ferrite interface. In contrast, during isothermal aging, nucleation of ɛ-copper precipitation occurs at dislocations. In the three different chemistries investigated, the increase in strength associated with copper during aging results only in a small decrease in impact toughness, implying that copper precipitates do not seriously impair toughness, and can be considered as a viable strengthening element in microalloyed steels. Precipitation of fine-scale niobium carbides occurs extensively at dislocations and within ferrite matrix together with vanadium carbides. In the presence of titanium, titanium carbides act as a nucleus for niobium carbide formation. Irrespective of the nature of carbides, copper precipitates and carbides are mutually exclusive.
R. D. Misra et al., "Precipitation Behavior During Thin Slab Thermomechanical Processing and Isothermal Aging of Copper-bearing Niobium-Microalloyed High Strength Structural Steels: The Effect on Mechanical Properties," Materials Science and Engineering A, vol. 528, no. 29-30, pp. 8772-8780, Elsevier, Jan 2011.
The definitive version is available at http://dx.doi.org/10.1016/j.msea.2011.08.047
Materials Science and Engineering
Keywords and Phrases
Microalloyed steels; Copper; Mechanical properties
International Standard Serial Number (ISSN)
Article - Journal
© 2011 Elsevier