In Situ Fabrication of TiC/Ti-Matrix Composites by Laser Directed Energy Deposition

Area of Science:

• Materials Science
• Additive Manufacturing
• Composite Materials

Background:

• Titanium carbide (TiC) reinforced titanium (Ti) matrix composites (TMCs) offer potential for enhanced mechanical properties.
• Fabrication of crack-free TMCs with controlled TiC content remains a challenge.

Purpose of the Study:

• To fabricate crack-free TiC/Ti composites using Direct Energy Deposition (DED).
• To investigate the effect of varying TiC content on the microstructure, microhardness, tensile strength, and wear behavior of the composites.

Main Methods:

• Utilized Direct Energy Deposition with a dual-feeder system to concurrently deliver Ti and TiC powders.
• Varied TiC content from 0 to 15 wt.% in the Ti matrix.
• Characterized microstructures, microhardness, tensile properties, and wear rates of the fabricated composites.

Main Results:

• Successfully fabricated crack-free TiC/Ti composites with controlled TiC distribution.
• Microhardness increased from 192 HV$_{0.2}$ (pure Ti) to 300 HV$_{0.2}$ (15 wt.% TiC).
• Tensile strength increased to 725 MPa, while elongation decreased to 0.62%.
• Optimal wear resistance was observed in the hypoeutectic region (3 wt.% TiC) with a wear rate of 2.45 mm$^3$/N·m.

Conclusions:

• DED with a dual-feeder system is effective for producing crack-free TiC/Ti composites.
• TiC reinforcement significantly improves hardness and tensile strength through solid solution and fine grain strengthening.
• The study provides a method to tailor TiC morphologies for enhanced TMC properties.