Characterization of 5356 Aluminum Walls Produced by Wire Arc Additive Manufacturing (WAAM)

Area of Science:

• Materials Science
• Manufacturing Engineering
• Additive Manufacturing

Background:

• Wire arc additive manufacturing (WAAM) offers high deposition rates for large parts but faces challenges like porosity in aluminum alloys.
• Porosity, residual stresses, and cracking are critical issues affecting the mechanical integrity of WAAM-produced aluminum components.

Purpose of the Study:

• To analyze the porosity of AA5356 aluminum alloy walls produced by WAAM.
• To investigate the relationship between process parameters (travel speed, cooling time, path strategy) and porosity.
• To determine the correlation between porosity and tensile properties of the manufactured parts.

Main Methods:

• Wire arc additive manufacturing (WAAM) using a Fronius cold metal transfer system to produce AA5356 walls.
• Computed tomography (CT) for detailed porosity analysis of machined specimens.
• Tensile testing to evaluate ultimate tensile strength and elongation.

Main Results:

• Increasing travel speed and cooling time reduces pore diameter by minimizing heat input and accumulation.
• A higher travel speed from 700 to 950 mm/min resulted in a slight decrease in total pore volume (0.42 to 0.36 mm³).
• The 'back and forth' path strategy showed slightly higher ultimate tensile strength and elongation compared to the 'go' strategy.

Conclusions:

• Optimizing travel speed and cooling time is crucial for reducing porosity in WAAM aluminum parts.
• The study found no direct correlation between porosity levels (below 0.12% total volume) and the measured ultimate tensile strength or yield strength.
• WAAM process parameters significantly influence porosity, but its impact on tensile strength within the tested range was minimal for AA5356.