Microstructure and Tensile Properties of Cu-Ti Composites Deposited by Cold Spray Additive Manufacturing

Area of Science:

• Materials Science
• Additive Manufacturing
• Surface Engineering

Background:

• Copper-titanium (Cu-Ti) composite coatings are valuable for various applications.
• Cold spray additive manufacturing (CSAM) offers a promising route for fabricating these coatings.
• Optimizing CSAM process parameters is crucial for achieving desired material properties.

Purpose of the Study:

• To investigate the effects of propellant gas and post-heat treatment temperatures on Cu-Ti composite coatings fabricated by CSAM.
• To understand the microstructural evolution and its correlation with tensile properties.
• To identify optimal processing conditions for enhanced strength and ductility.

Main Methods:

• Fabrication of Cu-Ti composite coatings (6 wt.% Ti) using CSAM with nitrogen propellant gas.
• Systematic variation of propellant gas temperatures (600-800 °C) and post-heat treatment temperatures (350-400 °C).
• Evaluation using tensile testing, microhardness, and fractography analysis.

Main Results:

• Increased propellant gas temperature enhanced copper particle plastic deformation, improving deposit density and bonding.
• The 800 °C propellant gas specimen showed a 69% increase in tensile strength (338 MPa) compared to the 600 °C specimen.
• Post-heat treatment at 400 °C achieved 15% elongation while maintaining >270 MPa tensile strength, mitigating work hardening.

Conclusions:

• High propellant gas temperatures promote dense lamellar structures, enhancing strength.
• Post-heat treatment induces recrystallization, optimizing ductility.
• Synergistic optimization of strength and ductility in CSAM-fabricated Cu-Ti composites is achievable through controlled processing parameters.