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Title: On apparent activation energies of creep in nickel-base superalloys

Abstract

Generally, the steady state is well defined in the creep curve in pure metals and some single-phase alloys. In this case, the diagram log {dot {epsilon}} vs. {epsilon} (where {epsilon} is the plastic strain) shows an extensive range of strain where the steady-state creep rate is maintained approximately constant. However, in those materials which present an unstable substructure, such as the particle strengthened alloys, the strain rate reaches a momentary minimum value instead of a steady-state creep rate. In this way, the minimum creep rate is observed in a regime of unstable transition. In this work, a study of the apparent activation energy of creep for IN-X750 was performed, using the differential temperature step technique. The tests were carried out near the minimum strain rate in order to analyze the influence of the material substructure on the values of the apparent activation energy.

Authors:
 [1];  [2]
  1. Univ. Nacional del Centro de la Provincia de Buenos Aires (Argentina). Inst. de Fisica de Materiales Tandil|[Comision de Investigaciones Cientificas de la Provincia de Buenos Aires (Argentina)
  2. Univ. de Buenos Aires (Argentina). Dept. de Fisica
Publication Date:
OSTI Identifier:
691353
Resource Type:
Journal Article
Journal Name:
Scripta Materialia
Additional Journal Information:
Journal Volume: 41; Journal Issue: 8; Other Information: PBD: 10 Sep 1999
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CREEP; NICKEL BASE ALLOYS; ACTIVATION ENERGY; STRAIN RATE; STRESSES; TEMPERATURE RANGE 0400-1000 K

Citation Formats

Picasso, A.C., and Marzocca, A.J. On apparent activation energies of creep in nickel-base superalloys. United States: N. p., 1999. Web. doi:10.1016/S1359-6462(99)00229-8.
Picasso, A.C., & Marzocca, A.J. On apparent activation energies of creep in nickel-base superalloys. United States. doi:10.1016/S1359-6462(99)00229-8.
Picasso, A.C., and Marzocca, A.J. Fri . "On apparent activation energies of creep in nickel-base superalloys". United States. doi:10.1016/S1359-6462(99)00229-8.
@article{osti_691353,
title = {On apparent activation energies of creep in nickel-base superalloys},
author = {Picasso, A.C. and Marzocca, A.J.},
abstractNote = {Generally, the steady state is well defined in the creep curve in pure metals and some single-phase alloys. In this case, the diagram log {dot {epsilon}} vs. {epsilon} (where {epsilon} is the plastic strain) shows an extensive range of strain where the steady-state creep rate is maintained approximately constant. However, in those materials which present an unstable substructure, such as the particle strengthened alloys, the strain rate reaches a momentary minimum value instead of a steady-state creep rate. In this way, the minimum creep rate is observed in a regime of unstable transition. In this work, a study of the apparent activation energy of creep for IN-X750 was performed, using the differential temperature step technique. The tests were carried out near the minimum strain rate in order to analyze the influence of the material substructure on the values of the apparent activation energy.},
doi = {10.1016/S1359-6462(99)00229-8},
journal = {Scripta Materialia},
number = 8,
volume = 41,
place = {United States},
year = {1999},
month = {9}
}