| Numéro |
J. Phys. Colloques
Volume 47, Numéro C7, Novembre 1986
33rd International Field Emission Symposium / 33ème Symposium International d'Emission de Champ
|
|
|---|---|---|
| Page(s) | C7-223 - C7-231 | |
| DOI | https://doi.org/10.1051/jphyscol:1986739 | |
J. Phys. Colloques 47 (1986) C7-223-C7-231
DOI: 10.1051/jphyscol:1986739
ALLOY CARBIDE PRECIPITATION IN A HIGH COBALT-NICKEL SECONDARY HARDENING STEEL
J.A. LIDDLE1, 2, G.D.W. SMITH1, 2 et G.B. OLSON1, 21 Department of Metallurgy and Science of Materials, University of Oxford, Parks Road, GB-Oxford 0X1 3PH, Great-Britain
2 Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, U.S.A.
Abstract
The process of alloy carbide precipitation in a high cobalt-nickel secondary hardening steel, AF1410 (Fe - 14 wt%Co - 10%Ni - 2%Cr - 1%Mo - 0.16%C) has been studied by FIM and atom probe techniques. The evolution of the alloy carbides has been followed in detail for the standard heat treatment temperature of 510°C. The first evidence of brightly-imaging solute clusters is observed after an ageing time of 1 minute, and the first traces of a rod-like morphology emerge after 30 minutes. Very slow growth of the rod-like carbides takes place between 30 minutes and 5 hours ageing, accompanied by a slow decrease in hardness. This is followed by rapid coarsening and spheroidisation, during which a marked loss of hardness occurs. The size and composition variation of the carbides has been followed throughout the ageing treatment. A model for the growth and coarsening of the particles is presented.