Münster 1997 – wissenschaftliches Programm
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M: Metallphysik
M 10: Kristallplastizit
ät I
M 10.5: Vortrag
Dienstag, 18. März 1997, 16:30–16:50, S 8
Mechanical Behaviour and Microstructural Evolution in the Single C= rystal Superalloy SC16 — •D. Mukherji1, H. Gabrisch1, W. Chen2, H.J. Fecht2, and R.P. Wahi1 — 1Hahn-Meitner-Institut GmbH, Berlin — 2Institut für Metallforschung, Technische Universität Be= rlin
Mechanical testing at constant strain rates (tensile tests) and constant loads (creep tests) of the single crystal nickel base superalloy SC16 at 1223 K shows that after an initial hardening the alloy softens during deformation under all testing conditions. Within the testing range covered in the present study two different deformation mechanisms are identified to occur in different regimes of testing. In the present contribution we analyse the softening behaviour observed in the low strain rate regime. In this regime the softening is accompanied by a morphological change in gamma-prime precipitates (rafting). We show that the observed microstructural instability leads to an increase in the spacing between the gamma-prime particles. This effect quantitatively accounts for the observed softening in this test regime.