Optimization and validation of a dislocation density based constitutive model for as-cast Mg-9%Al-1%Zn

• A dislocation density-based constitutive model, including effects of microstructure scale and temperature, was calibrated to predict flow stress of an as-cast AZ91D (Mg-9%Al-1%Zn) alloy. Tensile stress-strain data, for strain rates from 10-4 up to 10-1 s-1 and temperatures from room temperature up to 190 °C were used for model calibration. The used model accounts for the interaction of various microstructure features with dislocations and thereby on the plastic properties. It was shown that the Secondary Dendrite Arm Spacing (SDAS) size was appropriate as an initial characteristic microstructural scale input to the model. However, as strain increased the influence of subcells size and total dislocation density dominated the flow stress. The calibrated temperature-dependent parameters were validated through a correlation between microstructure and the physics of the deforming alloy. The model was validated by comparison with dislocation density obtained by using Electron Backscattered Diffraction (EBSD) technique.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Metallurgi och metalliska material (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Metallurgy and Metallic Materials (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Annan materialteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Other Materials Engineering (hsv//eng)

Nyckelord

Casting methods

Characterization

Magnesium alloy

Optimization

Physically-based model

Plasticity

Aluminum

Aluminum alloys

Constitutive models

Magnesium castings

Microstructure

Plastic flow

Strain rate

Ternary alloys

Zinc

Zinc alloys

Zirconium alloys

Casting method

Dislocation densities

Electron back-scattered diffraction

Model calibration

Physically based modeling

Secondary dendrite arm spacing

Temperature dependent

Tensile stress strain

Magnesium alloys

Material Mechanics

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