HEAs represent a paradigm shift from dilute alloys to concentrated solid solutions. The combination of ML and AM is transformative: ML navigates the astronomical composition space, while AM enables rapid fabrication of complex geometries with site-specific compositions.
ML for High Entropy Alloys in AM
Machine learning accelerates composition design and process optimization for multi-principal element alloys in additive manufacturing
Topic Survey
Area
Advanced Alloys + ML
Papers (250+ cit)
1,200+
Total Citations
650,000+
Typical Systems
CoCrFeNi, AlCoCrFeNi, TiZrNbTa
AM Processes
LPBF, DED, WAAM
Composition Space
10^6+ possible alloys
High entropy alloys (HEAs) contain 5+ principal elements in near-equiatomic ratios, creating vast composition spaces impossible to explore experimentally. Machine learning combined with additive manufacturing enables rapid discovery and production of novel HEAs with exceptional properties - high strength, corrosion resistance, and high-temperature performance.
Contents
Overview
1,200+
Capstone Papers
10^6+
Possible Compositions
>1 GPa
Typical Yield Strength
R2>0.90
ML Prediction Acc.
ML for Composition Design
Design Parameters
ML models predict phase formation and properties from composition-derived features:
- VEC: Valence electron concentration - determines FCC vs BCC
- Delta: Atomic size mismatch - affects solid solution stability
- Omega: Thermodynamic parameter - entropy vs enthalpy balance
- Electronegativity: Difference affects intermetallic formation
Phase Prediction
| Phase | ML Method | Key Features | Accuracy |
|---|---|---|---|
| Single-phase FCC | Random Forest | VEC > 8, low delta | 92% |
| Single-phase BCC | SVM | VEC < 6.87 | 89% |
| Dual phase | Neural Network | Intermediate VEC | 85% |
| Intermetallic | Gradient Boosting | High delta, low omega | 87% |
Inverse Design
Given target properties, ML finds optimal compositions:
- Bayesian optimization: Efficient search of composition space
- Genetic algorithms: Multi-objective (strength + ductility)
- VAE/GAN: Generative models for novel compositions
- Active learning: Sequential experiment design
Property Prediction
Mechanical Properties
| Property | Best Model | Input Features | R2 Score |
|---|---|---|---|
| Yield strength | XGBoost | Composition, VEC, delta, process | 0.91 |
| Ultimate tensile strength | Neural Network | Composition + microstructure | 0.89 |
| Elongation | Gradient Boosting | Composition, phase fraction | 0.82 |
| Hardness | Random Forest | Composition, delta | 0.93 |
High-Temperature Properties
- Creep resistance: Critical for turbine applications
- Oxidation behavior: Al/Cr content optimization
- Thermal stability: Phase decomposition prediction
Corrosion Resistance
- Pitting potential: ML from electrochemical data
- Passivation: Cr, Mo content effects
- Stress corrosion: Combined mechanical-chemical prediction
AM Processing of HEAs
LPBF (Laser Powder Bed Fusion)
Most common AM process for HEAs:
- Powder production: Gas atomization of pre-alloyed powder
- Cracking susceptibility: ML predicts crack-prone compositions
- Parameter optimization: Energy density windows for each alloy
- Microstructure: Columnar to equiaxed transition control
DED (Directed Energy Deposition)
- In-situ alloying: Elemental powder mixing for compositional gradients
- Functionally graded: Varying composition through the build
- Repair applications: HEA cladding on conventional alloys
Process-Property Relationships
| HEA System | Optimal Energy Density | Key Challenge | ML Solution |
|---|---|---|---|
| CoCrFeMnNi | 60-100 J/mm3 | Mn evaporation | Composition compensation |
| AlCoCrFeNi | 80-120 J/mm3 | Al segregation | Scan strategy optimization |
| CoCrFeNiTi | 70-110 J/mm3 | Intermetallic precipitation | Cooling rate control |
| TiZrNbTaMo | 100-150 J/mm3 | High melting point | Preheat optimization |
Applications
Aerospace
- Turbine blades: High-temperature strength, creep resistance
- Combustor liners: Oxidation resistance
- Landing gear: High strength-to-weight ratio
Nuclear
- Radiation resistance: Self-healing defect structures
- Cladding materials: Corrosion under irradiation
Tooling & Wear
- Cutting tools: Hardness + toughness combination
- Die inserts: Thermal fatigue resistance
Key Papers
High-entropy alloys: A critical review
Machine learning in materials science for HEA design
Additive manufacturing of high-entropy alloys: A review
Data-driven design of HEAs with targeted properties