Process-Microstructure-Property Characteristics of Aluminum Walls Fabricated by Hybrid Wire Arc Additive...

Area of Science:

• Materials Science
• Manufacturing Engineering
• Metallurgy

Background:

• Wire Arc Additive Manufacturing (WAAM) offers a cost-effective route for large aluminum components.
• WAAM processes often face challenges with heat accumulation and coarse microstructures, impacting performance.
• Existing WAAM methods can lead to anisotropic properties and reduced mechanical integrity.

Purpose of the Study:

• To investigate a hybrid unified additive deformation manufacturing process (UAMFSP) integrating friction stir processing (FSP) into WAAM.
• To compare the thermal profiles and microstructural characteristics of UAMFSP-fabricated walls against Metal Inert Gas (MIG)-based WAAM walls.
• To evaluate the microhardness improvements offered by the UAMFSP method over conventional WAAM.

Main Methods:

• Fabrication of comparative wall structures using UAMFSP and MIG-based WAAM.
• Infrared (IR) thermography for monitoring and analyzing thermal profiles during the manufacturing process.
• Optical microscopy and quantitative image analysis for characterizing grain size and morphology.
• Microhardness testing (Vickers HV0.2) to assess mechanical properties.

Main Results:

• MIG-based WAAM exhibited significant heat accumulation (peak temperatures 870-1000 °C), while UAMFSP maintained lower, uniform profiles (<400 °C) via mechanical stirring.
• MIG walls showed coarse, dendritic grains (mean area ~314 µm²), whereas UAMFSP produced refined, equiaxed grains (mean area ~10.9 µm²).
• UAMFSP resulted in a 45.8% increase in microhardness compared to MIG-based WAAM (75.8 HV vs. 52.0 HV).

Conclusions:

• The UAMFSP process effectively mitigates the thermal and microstructural limitations inherent in traditional WAAM.
• Hybrid additive-deformation strategies, like UAMFSP, offer a promising pathway for enhancing the performance of additively manufactured aluminum components.
• This research provides a foundation for advancing hybrid additive-deformation techniques for thicker builds, diverse alloys, and real-world mechanical assessments.