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Microstructural Evolution and Life Evaluation during Creep/Rupture Process of a Single Crystal Superalloy
Last modified: 2013-05-06
Abstract
Creep and stress rupture tests were conducted at elevated temperatures
on a single crystal nickel base superalloy. Creep process may be divided into
different stages, one is initial stage characterized by dislocation slip and the other
is rafting one characterized by γ′ phase rafting. The rupture results show that the
alloy with [001] and [111] orientations exhibit superior rupture strength to that
with [011] at 980°C, which may be ascribed to different dislocation slip
mechanism, but the difference among stress rupture strength of the alloy with
three orientations is relatively small at 1070°C. A damage parameter is deduced
on the quantitative relationship between applied stress and basic mechanical
properties of the material, i.e. elastic modulus, yield stress and ultimate tensile
strength. The model can be used to predict the rupture life of the alloy with any
orientation at high temperature. The prediction values agree well with test data.
on a single crystal nickel base superalloy. Creep process may be divided into
different stages, one is initial stage characterized by dislocation slip and the other
is rafting one characterized by γ′ phase rafting. The rupture results show that the
alloy with [001] and [111] orientations exhibit superior rupture strength to that
with [011] at 980°C, which may be ascribed to different dislocation slip
mechanism, but the difference among stress rupture strength of the alloy with
three orientations is relatively small at 1070°C. A damage parameter is deduced
on the quantitative relationship between applied stress and basic mechanical
properties of the material, i.e. elastic modulus, yield stress and ultimate tensile
strength. The model can be used to predict the rupture life of the alloy with any
orientation at high temperature. The prediction values agree well with test data.
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