Metallurgical Analysis Skill

Purpose

The Metallurgical Analysis skill provides specialized capabilities for characterizing metallic materials through metallographic techniques, enabling systematic evaluation of microstructure, grain size, phase distribution, and inclusion content per industry standards.

Capabilities

Metallographic preparation protocol selection
Etching reagent selection for different alloys
Grain size measurement (ASTM E112, intercept method)
Phase fraction quantification (point count, image analysis)
Inclusion rating (ASTM E45)
Banding and segregation assessment
Prior austenite grain boundary revelation
Weld microstructure evaluation (HAZ mapping)

Usage Guidelines

Sample Preparation

Sectioning
- Select appropriate cutting method (abrasive, EDM, precision saw)
- Minimize heat input to prevent microstructural changes
- Identify orientation relative to processing direction
Mounting
- Choose mount type (hot compression, cold setting)
- Add conductive filler for SEM/EBSD samples
- Consider edge retention requirements
Grinding and Polishing
- Follow systematic grit progression (120 to 1200 to diamond)
- Use appropriate lubricant and rotation direction
- Verify scratch-free surface before etching

Etching Selection

| Alloy System | Etchant | Purpose | |--------------|---------|---------| | Carbon steels | 2% Nital | General microstructure | | Stainless steel | Vilella's | Martensitic structures | | Aluminum | Keller's | Grain boundaries, precipitates | | Titanium | Kroll's | Alpha-beta microstructure | | Copper | FeCl3/HCl | Grain boundaries | | Nickel superalloys | Glyceregia | Gamma prime, carbides |

Grain Size Measurement

ASTM E112 Methods
- Comparison method: Match to standard charts
- Planimetric method: Count grains in known area
- Intercept method: Count grain boundary intersections
Calculation
- Apply magnification correction
- Use minimum 5 fields for statistical validity
- Report ASTM grain size number with standard deviation
Special Cases
- Duplex structures: Report both phases separately
- Elongated grains: Measure aspect ratio
- Prior austenite: Use specific etchants (picric acid based)

Inclusion Rating (ASTM E45)

Method Selection
- Method A: Worst field rating
- Method D: Quantitative measurement
- Specify inclusion type (A, B, C, D sulfides, oxides)
Reporting
- Include severity (thin, heavy) and length
- Note distribution (random, stringer, cluster)
- Compare to specification limits

Process Integration

MS-002: Electron Microscopy Characterization
MS-017: Root Cause Failure Analysis

Input Schema

{
  "sample_id": "string",
  "alloy_system": "steel|aluminum|titanium|copper|nickel",
  "alloy_grade": "string",
  "analysis_type": "grain_size|phase_fraction|inclusion|weld_eval",
  "magnification": "number",
  "etchant_used": "string"
}

Output Schema

{
  "sample_id": "string",
  "grain_size": {
    "astm_number": "number",
    "average_diameter": "number (microns)",
    "standard_deviation": "number",
    "method": "string"
  },
  "phase_fractions": [
    {
      "phase": "string",
      "fraction": "number (percent)",
      "morphology": "string"
    }
  ],
  "inclusion_rating": {
    "method": "string",
    "type_a": "number",
    "type_b": "number",
    "type_c": "number",
    "type_d": "number"
  },
  "observations": "string"
}

Best Practices

Document complete preparation procedure for reproducibility
Use consistent magnification within a comparative study
Apply appropriate etching time - under-etched is better than over-etched
Verify grain boundaries are fully revealed before measurement
Use image analysis software for quantitative phase measurements
Include representative micrographs in reports

Integration Points

Connects with Electron Microscopy for high-resolution analysis
Feeds into Failure Analysis for metallographic investigation
Supports Mechanical Testing for structure-property correlation
Integrates with Heat Treatment Optimization for process development