A model approach to metals

(1)

A model approach to metals

Wei SHA

(2)

Metals

The most important materials

Other materials

(3)

Microstructure

(4)

Microstructure

Heat treatment: steel hardness and Al precipitation

0.0625 0.125 0.25 0.5 1 2 4 8 16 32 64

Ageing Time, h

H

(5)

Mechanical processing

(6)

Gasar

Gas-reinforced metals

(7)

Computer software systems

Predicting microstructures

Predicting properties

(8)

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Modelling methodologies

1) The Johnson-Mehl-Avrami method and its adaption to

continuous cooling and heating

2) Finite element method

3) Phase field method

4) Atomistic simulation

5) Neural network method

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Neural network

Natual

Artificial

Training data set

INPUTS OUTPUTS

X1 X2 X3 X4 Y1 Y2

0.345 -0.701 1.000 0.002 0.678 -0.243

…. …. …. …. …. ….

Input

Layer

Hidden

Layer

Output

Layer

Neural Network

The human brain contains 1010_{– 10}11_neurons

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Titanium alloy

Phase transformation

Fr3T

(12)

Furnace Time-temperature path In-situ monitoring

The Model

SM_Monitoring.exe

Example of simulation and monitoring

Nucleation and growth of the



phase in Ti6242

(13)

Composition-processing-temperature-mechanical properties TTT diagrams

Fatigue life CCT diagrams Microhardness profile

Modules and graphical user interfaces

Simulation and modelling of different correlations

(14)

Gasar

Pores

Drenchev, Sobczak, Sha, Malinov, Journal of Materials Science, 40, 2005, 2525.

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1) Pass the 9 dots with

3 changes of direction

2) Plant 10 trees in 5 lines,

each line having 4 trees

(16)

Industrial applications

Optimization of the alloy composition

Optimisation

Criteria

Heat Treatment

Loops for Temperature

Loops for Alloy Composition

Find

Alloy composition with max strength at 420°C

Fix

Heat treatment = Annealing T = 420°C Tensile strength (420°C) = 932 MPa;

Yield strength = 665 MPa; Elongation = 10%;

Modulus of elasticity = 94 GPa; Fatigue strength = 448 MPa; Fracture toughness = 101 MPa m1/2

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Industrial applications

Centrifugal casting process of composite

(18)

10 s

radius r vol. _fraction

5 s

15 s

0 s

25 s, completed

20 s

Industrial applications

SiC particle distribution during casting of Al alloy

(19)

Industrial applications

Hot spot and gas cavity in centrifugal casting

Hot spot

Gas cavity

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A model approach to metals