Tool for automatic macrozone characterization from EBSD data sets of titanium alloys

Area of Science:

• Materials Science
• Metallurgy
• Crystallography

Background:

• Microtexture heterogeneities, known as macrozones, are prevalent in titanium forgings due to thermomechanical processing.
• These macrozones, characterized by grains with similar crystallographic orientation, reduce resistance to crack propagation.
• A link exists between macrozones and reduced cold-dwell-fatigue performance in gas turbine engine components.

Purpose of the Study:

• To develop and apply a computational tool for automatic macrozone identification from electron backscatter diffraction (EBSD) data.
• To implement a more conservative approach considering both c-axis tilting and rotation for macrozone definition.
• To enhance the characterization of microtexture heterogeneities in titanium forgings.

Main Methods:

• Development of a MATLAB-based computational tool for macrozone identification.
• Utilizing EBSD data sets for texture analysis.
• Applying criteria based on disorientation angle and density-fraction for macrozone detection.

Main Results:

• Successful automatic identification of macrozones in titanium forgings.
• Validation of clustering efficiency using pole-figure plots.
• Demonstration of the tool's applicability to both equiaxed and bimodal microstructures.

Conclusions:

• The developed computational tool provides an effective method for macrozone identification.
• The conservative approach improves the definition of macrozone boundaries and disorientation spread.
• This tool aids in understanding and mitigating the impact of macrozones on fatigue performance.