Mechanical Response and Microstructure Evolution of TA1 Titanium Under Normal Ultrasonic Vibration Processing

Area of Science:

• Materials Science
• Mechanical Engineering
• Physics

Background:

• Ultrasonic vibration (UV) is known for its acoustoplasticity effect in plastic forming.
• Most research applies UV longitudinally, unlike real-world sheet metal forming conditions.

Purpose of the Study:

• Investigate normal UV-assisted uniaxial tension on TA1 thin sheets.
• Analyze mechanical properties and microstructure evolution under normal UV.
• Elucidate the micro-level UV softening mechanism.

Main Methods:

• Performed normal UV-assisted tension tests on TA1 thin sheets.
• Analyzed macro-mechanical behavior using stress-strain curves at varying ultrasonic amplitudes and strain rates.
• Characterized fracture morphology and microstructure evolution via scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD).

Main Results:

• Achieved up to 20% stress reduction with a 13.9 μm ultrasonic amplitude.
• Observed a shift from ductile to brittle fracture with increasing UV amplitude.
• Decreased low-angle grain boundary fraction, kernel average misorientation (KAM), and geometrically necessary dislocation (GND) density.
• Diversified plastic deformation mechanisms due to normal UV superposition.

Conclusions:

• Normal UV significantly reduces deformation resistance in TA1 thin sheets.
• Microstructural changes, including reduced LAGB, KAM, and GND, explain the softening effect.
• Normal UV offers a promising method to enhance plastic forming processes.