Characterization of microtexture in Ti-6Al-4 V using ultrasonic polar forward scattering

Area of Science:

• Materials Science
• Non-Destructive Testing
• Mechanical Engineering

Background:

• Manufacturing Ti6Al4V billets creates microtextured regions (MTRs) that may increase cold dwell fatigue risk in forged components.
• MTRs can cause stress concentrations, potentially leading to fatigue crack initiation, making their detection and orientation critical.
• Current ultrasonic inspections for Ti6Al4V billets primarily detect hard-alpha inclusions but can yield false positives due to MTRs.

Purpose of the Study:

• To investigate and quantify the ultrasonic scattering behavior of suspected MTRs in Ti6Al4V.
• To determine the relationship between MTR orientation (C-axis) and ultrasonic scattering patterns.
• To improve the detection and characterization of MTRs for enhanced material integrity and aerospace safety.

Main Methods:

• Utilized ultrasonic scanning with focused transducers to identify potential MTRs in a Ti6Al4V billet.
• Prepared 2-inch cubes from the billet, precisely locating MTRs for detailed analysis.
• Performed through-transmission ultrasonic measurements using a custom rotating fixture to capture angular scattering dependencies and compared results with DREAM.3D modeling.

Main Results:

• Quantified the ultrasonic through-transmission polar scattering from MTRs, revealing strong angular dependencies.
• Demonstrated a unique experimental approach to characterize MTR scattering.
• Established a basis for comparing experimental scattering data with microstructure models.

Conclusions:

• The study provides critical insights into the ultrasonic scattering characteristics of MTRs in Ti6Al4V.
• Understanding MTR scattering is essential for accurate detection and C-axis orientation quantification.
• Improved MTR characterization can enhance non-destructive testing reliability, contributing to safer aerospace components.