# Mat Calphad Property Diagram

> Calculate temperature-dependent thermodynamic properties like Equilibrium Phase Fractions for a specific alloy composition using CALPHAD models.

- Skill: `learningmatter-mit/mat-calphad-property-diagram` (Agent Skill, multi-file: 4 files)
- Install (CLI): `npx skillmds@latest add learningmatter-mit/mat-calphad-property-diagram`
- Raw SKILL.md: https://api.skillmd.com/api/skills/learningmatter-mit/mat-calphad-property-diagram/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: learningmatter-mit (https://skillmd.com/u/learningmatter-mit)
- Updated: 2026-09-22
- Page: https://skillmd.com/skills/learningmatter-mit/mat-calphad-property-diagram

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# mat-calphad-property-diagram

## Goal
To predict the equilibrium phase stability, phase fractions, and other extensive thermodynamic properties for a fixed multi-component alloy at different temperatures using PyCalphad. Very useful for modeling solidification, heat treatment paths, and precipitation sequences.

## Instructions

### 1. Identify Thermodynamic Database
You must obtain a legitimate `.tdb` (Thermodynamic Data Base) file for the chemical system.

### 2. Plot Equilibrium Phase Fractions
Calculate what phases are present, and their molar fractions, across a cooling/heating schedule for a fixed composition.

```bash
# Env: calphad-agent
python .agents/skills/mat-calphad-property-diagram/scripts/plot_phase_fractions.py path/to/database.tdb --elements Element1 Element2 --composition Element2 0.3 --t-range 300 1000 10 --output research_dir/phase_fractions.png
```

- `--composition`: The solute element and its molar fraction (e.g. `Zn 0.3` means 30 mol% Zn).
- `--t-range`: `START STOP STEP` in Kelvin. Ensure solving across liquidus and solidus.

## Examples

Evaluating phase fractions for an Al-40%Zn alloy as it cools:
```bash
# Env: calphad-agent
python .agents/skills/mat-calphad-property-diagram/scripts/plot_phase_fractions.py .agents/skills/mat-calphad-phase-diagram/examples/Al-Zn/alzn_mey.tdb --elements Al Zn --composition Zn 0.4 --t-range 300 900 10 --output phase_fractions.png
```

## Constraints
- **Environments**: Scripts require the `calphad-agent` Conda environment.
- Only plots equilibrium step (lever-rule). For non-equilibrium fast solidification (Scheil), custom scripting is required.

## References
- Richard Otis and Zi-Kui Liu. "pycalphad: CALPHAD-based Computational Thermodynamics in Python." *Journal of Open Research Software* (2017).

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**Author:** Bowen Deng
**Contact:** [GitHub @learningmatter-mit](https://github.com/learningmatter-mit)