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