Harrer-Dorn and power law creep in Fe3wt%Si
1988
Ruano, Oscar Antonio | Wadsworth, J. | Sherby, O. D.
Harper-Dorn (H-D) creep is an example of Newtonian viscous flow and is usually observed at low stresses and high temperatures. The phenomenon was initially reported in coarse-grained pure A1 (i), but has since been confirmed in A1 and its alloys (2,3), Pb and Sn (4), ~-Zr (5), ~- Ti (6), ~-Fe (7), and p-Co (8) as well as a number of other dilute alloys (9). The mechanism responsible for H-D creep has been identified as a diffusion-controlled, dislocation-creep process (3,10-14). Recently, a H-D creep model based on the presence of an internal stress that both assists and inhibits power law creep was proposed and used to predict successfully the H-D creep regime in AI, Pb, and Sn (15). Also, in a recent paper by Ruano, Wadsworth, and Sherby (16), data on H-D creep in ~-Zr (5), ~-Ti (6), ~-Fe (7), and ~-Co (8) were described successfully using this model. Additionally, the H-D model was used to analyze other low stress data on seven other pure metals (~-Fe, Ni, Ag, p-Co, Cu, Mo, and Cr). The deformation mechanism in this latter group of seven metals was originally attributed to Nabarro-Berring (N-H) diffusional creep, although their creep rates were significantly faster than predicted by the N-H creep model (17). It was concluded by the present authors (16) that this group of metals deformed by H-D creep rather than by N-H creep.
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