Crack Control in Additive Manufacturing by Leveraging Process Parameters and Lattice Design

Area of Science:

• Materials Science
• Mechanical Engineering
• Additive Manufacturing

Background:

• Controlled crack propagation is crucial for enhancing material toughness and preventing catastrophic failures.
• Additive manufacturing offers novel design possibilities for tailoring material behavior, including fracture mechanics.

Purpose of the Study:

• To investigate the influence of lattice structure type, density, and laser energy on crack propagation and impact energy in additive manufactured components.
• To explore the potential of combining different lattice structures for guided crack deflection.

Main Methods:

• Fabrication of Ti-6Al-4V lattice structures (octet-truss and diamond) using powder bed fusion with varying densities (10%, 30%, 50%) and laser energies.
• Evaluation of fracture behavior and impact energy using Charpy impact tests on the manufactured specimens.
• Analysis of crack propagation patterns in relation to lattice architecture and processing parameters.

Main Results:

• Lattice type, density, and laser energy significantly affect crack propagation and impact energy.
• Octet-truss lattices exhibited straighter crack paths, while diamond lattices showed more random fracture patterns.
• Higher lattice densities and increased laser energy generally enhanced impact energy, with diamond lattices outperforming octet-truss in angle specimens.

Conclusions:

• Additive manufacturing enables the design of lattice structures for controlled fracture behavior.
• The interplay between lattice geometry, density, and processing parameters dictates crack propagation and energy absorption.
• Combining octet-truss and diamond lattice structures presents a promising strategy for guiding cracks and protecting critical components.