| Thermal visco-plastic constitutive relation
considering microstructure evolutions
This is a general thermal visco-plastic constitutive relation
which was developed in basis of the inversible thermal dynamics
and by means of meso-mechanics. The constitutive relation has
following features:
- Applicable to plastic and superplastic deformation of multiple
solid or porous metal, alloy and metal matrix composites in
room temperature or high temperature.
- Considers the coupling of macroscopic deformation and microstructure
evolution, the physical backgroud is all current material experimental
results and related conclusions.
- Include dynamic recrystallization, grain growth, void damage
and closing and influence of particles reinforced metal matrix
composites.
- Includes three microscopic deformation mechanism: dislocation
slipping, grain boundary sliding and diffusion creep.
- Includes the isotropic and kinematic strain hardening, strain
rate sensitivity and grain size sensitivity.
- Introduces the both average grain size and maximum grain size
difference for more precise description of grain evolution and
analysis of the defect of grains mixing (duplex grain structure).
- Able to be inserted into FEM simulation software.
The experimental research on recrystallization
and grain size evolution.
The tested materials are structure steel, super alloy, aluminum
alloy and etc. The tested microstructure evolution includes static
and dynamic recrystallization, grain growth and refining, void
growth, closing and welding.
Parameter identification.
The studied materials are Ti-6Al-4V, 7475Al for superplastic
constitutive relation and steel 26CrNi4MoV for thermal plastic
constitutive relation.
Computer software.
- SF2D/3D: FEM simulation of bulk forming process
with prediction of microstructure evolution..
- SS3D: FEM simulation of sheet forming process.
- RGM: Simulation of rigid body motion.
- PI: Special-purpose software for parameter identification.
Superplsticiy and
superplastic forming.
- Superplasticity: titanium alloy, aluminum alloy, copper alloy
and particles reinforced metal matrix composite.
- Superplastic forming: superplastic bulk forming and superplastic
sheet bulging forming.
Simulation and optimization of metal forming
process.
- Experimental simulation of heavy ingots forging.
- Numerical simulation of heavy ingots forging and grain size
prediction.
- Numerical simulation, optimization of hammer forging process.
- Numerical simulation of Stamping process, design and machining
of dies.
- Numerical simulation of superplastic tube forming and sheet
bulging.
New technology of forming process:
- FMV: a high-power consolidation process for heavy ingots.
- Thermal stress forming process of tube and sheet.
- Bending forming of tubes with lager diameter and thick wall
by hydro-press.
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