Solyx

Computational thermodynamics library for the JVM. CALPHAD-based phase equilibrium calculations for materials science and engineering.

Pre-release. Currently on hold. Core thermodynamic models and TDB parsing are implemented. A Gibbs minimizer — required for actual phase equilibrium calculations — is not yet implemented. The TDB parser is functional but not fully validated against the complete format spec. Results are not yet verified against experimental data. Do not use in production.

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What it does

Solyx computes thermodynamic equilibrium in multicomponent systems — which phases are stable, their compositions, and their fractions — using the CALPHAD methodology.

Targets researchers and engineers who need thermodynamic calculations on the JVM without depending on proprietary software (Thermo-Calc, Pandat) or Python.

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Installation

Not yet published to Maven Central. Currently available via source only.

// settings.gradle.kts
include(":solyx-core", ":solyx-thermo", ":solyx-calphad")

Maven Central publication is planned for v1.0.0 after experimental verification.

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Modules

Module	Description	Status
solyx-core	Numerical methods, units, error tracking	Complete
solyx-thermo	Thermodynamic models	Complete
solyx-calphad	TDB parser, Gibbs minimizer, phase diagrams	In progress

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Quick start

import dev.hivens.solyx.thermo.*
import dev.hivens.solyx.core.units.*

// Binary Fe-C system at 1200°C
val state = SystemState(
    composition = mapOf(
        Element.Fe to MoleFraction(0.98),
        Element.C  to MoleFraction(0.02)
    ),
    temperature = Kelvin.fromCelsius(1200.0)
)

// Ideal mixing entropy
val mixing = IdealMixing()
val g = mixing.compute(state)
println(g) // -975.3 J/mol

// Regular solution with Fe-C interaction
val solution = RegularSolution(
    interactions = listOf(
        RedlichKisterParameter(
            a = Element.Fe,
            b = Element.C,
            coefficients = listOf(JoulePerMole(-10_000.0))
        )
    )
)
val gTotal = solution.compute(state)

// Magnetic contribution for BCC Fe
val gMag = MagneticContribution.BCC_FE.compute(Kelvin.fromCelsius(1200.0))

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Design

• double precision throughout — sufficient for thermodynamic data accuracy
• Interval arithmetic for propagated uncertainty — every result carries error bounds
• Strongly typed units — Kelvin, JoulePerMole, MoleFraction — physically incorrect input is rejected at compile time or construction time
• Zero external dependencies in solyx-core
• Java-compatible API via @JvmStatic and explicit overloads

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Verification

Before v1.0.0, results will be verified against:

• Binary Fe-C phase diagram (NIST data)
• Binary Al-Cu phase diagram
• Liquidus/solidus temperatures vs published experimental data

Uncertainty bounds are reported on all results via Interval. If result.isReliable is false — the calculation did not converge to sufficient precision.

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License

MIT — no restrictions on commercial or academic use.

Roadmap

See ROADMAP.md for the full implementation plan and release schedule.