Fatigue Performance of Ti-6Al-4V Additively Manufactured Specimens with Integrated Capillaries of an Embedded...

Area of Science:

• Materials Science
• Mechanical Engineering
• Additive Manufacturing

Background:

• Additive manufacturing (AM) enables complex metal structures but poses challenges in predicting mechanical response and preventing failures.
• Structural Health Monitoring (SHM) is crucial for assessing the integrity of AM components.
• Ti-6Al-4V is a widely used alloy in demanding applications, making its fatigue behavior critical.

Purpose of the Study:

• To investigate the integration of a fatigue crack detection system using capillaries within Ti-6Al-4V specimens.
• To evaluate the effect of integrated capillaries on fatigue strength and initiation sites.
• To compare specimens produced by subtractive manufacturing versus additive manufacturing (Directed Energy Deposition - DED).

Main Methods:

• Four-point bending fatigue tests on Ti-6Al-4V specimens with and without integrated capillaries.
• Comparison of specimens produced via conventional subtractive manufacturing and laser-based DED AM.
• Finite Element Method (FEM) simulations to validate experimental findings.

Main Results:

• Drilled capillaries did not alter fatigue initiation location in wrought specimens.
• Roughness on DED-processed capillaries shifted fatigue initiation to the capillary surface.
• Fatigue performance was significantly reduced in specimens with additively manufactured (DED) capillaries.

Conclusions:

• The surface quality of integrated capillaries is paramount for maintaining structural integrity.
• AM processes like DED require careful control to ensure smooth capillary surfaces for effective SHM integration.
• Further research is needed to optimize AM processes for integrated SHM systems without compromising mechanical performance.