TY - JOUR
T1 - Numerical modelling of stress and strain evolution during solidification of a single crystal superalloy
AU - Panwisawas, Chinnapat
AU - Gebelin, Jean Christophe
AU - Warnken, Nils
AU - Broomfield, Robert W.
AU - Reed, Roger C.
PY - 2011/7/4
Y1 - 2011/7/4
N2 - During the manufacture of turbine blades from single crystal nickel-based superalloys by investment casting, recrystallisation can occur during solution heat treatment. The introduction of grain boundaries into a single crystal component is potentially detrimental to performance, and therefore manufacturing processes and/or component geometries should be chosen to prevent their occurrence. In this work, numerical models have been designed to enable a predictive capability for the factors influencing recrystallisation to be constructed. The root cause is plasticity on the microscale caused by differential thermal contraction of metal, mould and core; when the plastic deformation is sufficient, recrystallisation can take place subsequently. The models take various forms. First, one-dimensional models based upon static equilibrium have been produced - our calculations indicate that plastic strain is likely to take place in two temperature regimes: by creep between 1150°C and 1000°C and by tensile (time-independent) strain below 650°C. The idea of a strain-based criterion for recrystallisation is then proposed. Second, more sophisticated threedimensional calculations based upon the finite element method are carried out. Our predictions are compared critically with experimental information.
AB - During the manufacture of turbine blades from single crystal nickel-based superalloys by investment casting, recrystallisation can occur during solution heat treatment. The introduction of grain boundaries into a single crystal component is potentially detrimental to performance, and therefore manufacturing processes and/or component geometries should be chosen to prevent their occurrence. In this work, numerical models have been designed to enable a predictive capability for the factors influencing recrystallisation to be constructed. The root cause is plasticity on the microscale caused by differential thermal contraction of metal, mould and core; when the plastic deformation is sufficient, recrystallisation can take place subsequently. The models take various forms. First, one-dimensional models based upon static equilibrium have been produced - our calculations indicate that plastic strain is likely to take place in two temperature regimes: by creep between 1150°C and 1000°C and by tensile (time-independent) strain below 650°C. The idea of a strain-based criterion for recrystallisation is then proposed. Second, more sophisticated threedimensional calculations based upon the finite element method are carried out. Our predictions are compared critically with experimental information.
KW - Casting
KW - Recrystallisation
KW - Single Crystal Superalloys
KW - Solidification
UR - http://www.scopus.com/inward/record.url?scp=79960675297&partnerID=8YFLogxK
U2 - 10.4028/www.scientific.net/AMR.278.204
DO - 10.4028/www.scientific.net/AMR.278.204
M3 - Article
AN - SCOPUS:79960675297
SN - 1022-6680
VL - 278
SP - 204
EP - 209
JO - Advanced Materials Research
JF - Advanced Materials Research
ER -