Macroscopic Continuum Mechanics
• Elements > 0.5 cm
• Time steps > 1 s
• Average properties, e.g., yield stress
• Average stress
FZM –Solidification Simulation
Micro Mesh Dendrite(100x100x300 element - 1 e-6 cell size)
Weld pool Macro Analysis & Thermal Cycle
A B
Solidification Microstructure of Steel Weld Pool
John Goldak, Goldak Technologies Inc.
Mn MnC C
FZ Microstructure Framework
Multi scale multi-physics weld fusion zone framework
Partial Micro Mesh
80x80x80 element
0.75 e-6 m cell size
Left: Carbon field at b
Right: Carbon field at c
FZM – Solid State Solute Diffusion
FZM – Microstructure EvolutionPhase fields: Pearlite,
Ferrite, Austenite, Bainite,
Martensite and Hardness
80x80x80 element -
0.75 e-6 m cell size
FZM – Transient Stress-Strain
Effective plastic strain and stress
80x80x80 element - 0.75 e-6 m cell size
FZM – Room Temperature Uni-axial Tensile
Effective plastic strain and stress in uni-axial-tensile test at 4% macro strain
80x80x80 element - 0.75 e-6 m cell size
Transient Stress Analysis & Room Temperature Tensile Tests
Average stress vs strain in a uni-axial-tensile test. The sample is pulled in 20 displacement increments in the direction of dendrite axis
Gauss point stresses xx
Average stress xx
HAZ Microstructure Framework
Multi scale multi-physics framework
Austenite-Ferrite Phase Transformation
FerriteFerrite Pearlite
Synthetic Microstructure
P
P
P
P
P
P
P
Left: Initial Microstructure at a
Middle: Carbon field at c
Right: Carbon field at d
50x50x50 element
1 e-6 m cell size
John Goldak, Goldak Technologies Inc.
Austenite-ferrite Transformation & Solute Diffusion Solver
50x50x50 element
1e-6 & 5e-6 m cell size
Ferrite-pearlite
Fe-C pseudo-binary phase diagram
Diffusion control
Direct observation of austenitisation in 1005 C–Mn steel
(0.05 C – 0.31 Mn – 0.11 Ni–0.10 Cr – 0.18 Si – 0.008Mo)
Continuous heating : Isothermal heating to 975 C
with heating rates 1, 3 and 10 C/c
60s holding time at 975 C
Experiment (Palmer et.al 2011)
Simulation
Initial microstructure (ferrite-pearlite)
Microstructure att=180 s (ferrite-austenite)
John Goldak, Goldak Technologies Inc.
Austenite-Ferrite Transformation -Validation
Austenite-Ferrite Transformation - Validation
Progression of austenization transformation for heating 1 and 3 C/s heating rate - Simulation vs Experiments
Microstructure AnalysisPhase fields:Pearlite, Ferrite, Austenite, Bainite, Martensite and Hardness
50x50x50 element -1 e-6 m cell size
Transient Thermal Stress-Strain
Phase fields: Pearlite, Ferrite, Austenite, Bainaite, Martensite and Hardness50x50x50 element - 1 e-6 m cell size
Transient Stress Analysis & Room Temperature Tensile Tests
Phase fields: Pearlite, Ferrite, Austenite, Bainaite, Martensite and Hardness50x50x50 element - 1 e-6 m cell size
Gauss point stresses Average stress