PIRATES

Code for the Process-Scale Industry-Research Automated Texture Evolution Simulation (PIRATES).

Cite As

B.A. Begley, M.E. Hurley, M.S. David & V.M. Miller. "A Multiscale Model Predicting Site-Specific Texture Evolution: Application to Two-Phase Titanium Alloys." Integrating Materials and Manufacturing Innovation (Accepted). DOI.

Requirements and Dependencies

MATLAB (R2019a or later; earlier versions may work but are untested)

• Some dependencies (MTEX, VAMPYR) use the MATLAB Optimization Toolbox for additional features, but this toolbox is not necessary for PIRATES to be used as demonstrated in the manuscript.

MTEX open source MATLAB toolbox for crystallographic texture analysis

• Version 5.8.1 is a currently a hard version requirement. Version 5.10+ changed syntax that breaks compatibility with PIRATES, and I have not personally tested PIRATES with versions 5.8.2 or 5.9.X.

VAMPYR: VPSC Automation in MTEX for Polycrystal plasticitY Research

• Specifically, the linked vampyr8 branch which has syntax for VPSC 8, rather than the initial version for VPSC 7.

VPSC 8 The viscoplastic self-consistent polycrystal plasticity model

• A VPSC executable compiled for Windows 11 is included included with VAMPYR. Users with incompatible systems will have to compile VPSC from source code.

Initial Setup and Startup

In order to use PIRATES use the startup_mtex() function in your MTEX 5.8.1 directory (or install MTEX permanently to your MATLAB path) then use the startup_api() function in your VAMPYR directory. Navigate to the PIRATES directory.

PIRATES has one hardcoded path declaration in the Main3 script, which must direct PIRATES to the "magic_vpsc_box" directory in your VAMPYR installation.

% Define the location of the VAMPYR magic_vpsc_box and executable name.
vpsc_name = 'vpsc8.exe';
vpsc_path = 'C:\path_to_vampyr_installation\VPSC\magic_vpsc_box';

Setting up a run

The input files should be placed in Initial Inputs. This directory should include:

• alpha.sx and beta.sx. These are templates for the VPSC single crystal parameter files with pre-defined slip systems for α and β Ti.
• alpha.tex and beta.texx. VPSC texture input files.
• vpsc8.in. A template file for the main VPSC8 input file.
• tiny_increment.in. A template file for a VPSC deformation step.
• DEFORM Point Tracking Files as the .CSV file type.

Pre-Run Checklist

Settings that can be changed in Main3

These parameters control the simulation output.

Set the name of the point track file:

% Name of the DEFORM point tracking file (Which should be located in:
%   \Initial Inputs\)
pointTrackFile = 'DEF_PTR001_1600_2p.CSV';

Choose to apply a random recrystallization texture or an α BOR variant texture at specific points:

% Apply a random recrystallization texture to both phases at Reset Points?
isRandomRX = false; % If this is true, set isAlphaRandomVariant to false.

% Apply a random recrystallization texture to the beta phase and a BOR texture with
% random Alpha variant selection to the alpha phase at reset points?
isAlphaRandomVariant = false; % If this is true, set isRandomRX to false.

Choose to which β approach curve to use to calculate phase fractions:

• Currently, only the curve from Castro & Seraphin (1966) is implemented.
• More methods can be added to the switch statement in calcVfeqil.

% Choose from: 'Castro';
beta_approach_curve = 'Castro';

if ~ismember(curve_name, {'Castro'})
    error('Not an implemented Beta Approach Curve')
end

switch curve_name
    case 'Castro'
        T_celsius = (T_farenheit - 32) * 5 / 9;
        % Castro Seraphin 1966 Beta Approach Curve
        betaPF = (7.5+92.5*exp(-0.0085*(980-T_celsius)))/100;
end

Choose which steps recrystallization textures should be applied to (if any):

• Set reset_step = []; if it will be unused.

% =========================================================================
% --- RESET STEPS ---
% This is a new feature!
% Basically, these are steps where we are going to choose to manually override the
% texture in the VPSC input files, in order to apply (for instance) a recrystallization
% texture. This can't be done at every step, because this also zeros out the residual
% stresses in VPSC, which are necessary for accurate plastic rotation prediction.
% My recommendation is to set the steps to be at the end of a long isothermal hold.
% =========================================================================

reset_steps = [129 265 456]; %1400 4p
%reset_steps = [129 265 456]; %1600 4p
%reset_steps = [];

Choose the desired UpdateCRSS() function:

• UpdateCRSS_powerlaw() is the method used for the vast majority of the manuscript.
• UpdateCRSS_combined() was used to demonstrate non-fixed CRSS ratios.
• UpdateCRSS_linear() is a slightly simplified version of UpdateCRSS_combined().

[CRSS_basal, CRSS_prism, CRSS_pyra, CRSS_pyrca, CRSS_beta] = UpdateCRSS_powerlaw(Tk);
run.single_crystal{1,2}.Modes{1,1}.voceParams(1,1) = CRSS_prism;
run.single_crystal{1,2}.Modes{2,1}.voceParams(1,1) = CRSS_basal;
run.single_crystal{1,2}.Modes{3,1}.voceParams(1,1) = CRSS_pyra;
run.single_crystal{1,2}.Modes{4,1}.voceParams(1,1) = CRSS_pyrca;
run.single_crystal{1,1}.Modes{1,1}.voceParams(1,1) = CRSS_beta;
run.single_crystal{1,1}.Modes{2,1}.voceParams(1,1) = CRSS_beta;
run.single_crystal{1,1}.Modes{3,1}.voceParams(1,1) = CRSS_beta;

Name the output directory:

output_directory = 'outputs\1600_2p';
mkdir(fullfile(MainDir,output_directory));

Settings that can be changed in Analysis3:

These parameters control the plotting of figures from the simulation data.

Set the name of the point track file and output directory:

• These should be the same as in Main3.

pointTrackFile = 'DEF_PTR001_1600_2p.CSV';
folder = 'outputs\1600_2p';

Set the list of tracked points to analyze:

% List of points you want to analyze. Does not need to be the full list of points.
wantedPt = [1 2 4];

Give the points descriptive names:

% Names of points for labeling figures. Needs to be as long as the number of points in
% the point tracking file.
pos_name = {'ND_Offset', 'Center', 'TD_Offset', 'RD_Offset'};

Make sure the crystal symmetry parameters are the same as in Main3:

CSa = crystalSymmetry('622', [2.95 2.95 4.68], 'X||a', 'Y||b*', 'Z||c', 'color', 'light blue');
CSb = crystalSymmetry('432', [3.24 3.24 3.24], 'mineral', 'Titanium - Beta', 'color', 'light green');

Run Main3

By default, Analysis3 is called at the end of Main3, so plotting will run automatically.