Knowledge of correct flow stress curves of Ni-based alloys at high temperatures is of essential importance for reliable plastomechanical simulations in materials processing and for an effective planning and designing of industrial hot forming schedules like hot rolling or forging. The experiments are performed on a computer controlled servohydraulic testing machine at IBF. To avoid an inhomogeneous deformation due to the influence of friction and initial microstructure, a suitable specimen geometry and lubricant is used and a thermal treatment before testing has to provide a microstructure, similar to the structure of the material in the real process. The compression tests are performed within a furnace, which keeps sample, tools, and surrounding atmosphere on the defined forming temperature. The uniaxial compressions were carried out in the range of strain rates between 0.001 and $50s−1$ and temperatures between 950 and $1280°C.$ Furthermore, two-stage step tests are carried out to derive the work hardening and softening behavior as well as the recrystallization kinetics of the selected Ni-based alloys. At the end of this work a material model is adapted by the previously determined material data. This model is integrated into the Finite Element program LARSTRAN/SHAPE to calculate a forging process of the material Alloy 617.

1.
Herbertz
,
R.
, and
Wiegels
,
H.
,
1981
, “
Der Zylinderstauchversuch—ein geeigentes Verfahren zur Fließkurvenermittlung?
Stahl & Eisen
,
101
, p.
89
89
.
2.
Brand
,
A. J.
,
Karhausen
,
K.
, and
Kopp
,
R.
,
1996
, “
Microstructural Simulation of Nickel Base Alloy Inconel 718 in Production of Turbine Discs
,”
Mater. Sci. Technol.
,
12
, p.
963
963
.
3.
Roberts
,
W.
,
Boden
,
H.
, and
Ahlblom
,
B.
,
1979
, “
Dynamic Recrystallization Kinetics
,”
Met. Sci.
,
13
, p.
195
195
.
4.
McQueen, H. J., and Bourell, D. L., 1987, “Summary Review of Comparative Hot Workability of Metals in Different Crystal Structures,” Proc. Conf. on Formability and Metallurgical Structure, Sachdev and Embury, eds., TMS, Warrendale, PA, p. 341.
5.
Sellars, C. M., 1979, “The Physical Metallurgy of Hot Working,” Hot Working and Forming Processes, C. M. Sellars and G. J. Davies, eds., TMS, London, p. 3.
6.
Luton
,
M. J.
, and
Sellars
,
C. M.
,
1969
, “
Dynamic Recrystallization in Nickel and Nickel-Iron Alloys During High Temperature Deformation
,”
Acta Metall.
,
17
, p.
1033
1033
.
7.
Kopp, R., and Wolske, M., 2000, “Microstructure Simulation of Ni Based Alloys,” Proc. IVa Confere^ncia Internacional de Forjamento, Porto Alegre/Brazil, p. 42.
8.
Karhausen, K., 1994, “Integrierte Prozeß- und Gefu¨gesimulation bei der Warmumformung,” Dr.-Ing. thesis, Institute of Metal Forming, Aachen, Germany.
9.
Karhausen
,
K.
, and
Kopp
,
R.
,
1992
, “
Model for Integrated Process and Microstructure Simulation in Hot Forming
,”
Steel Res.
,
63
, p.
247
247
.
You do not currently have access to this content.