Advanced Carbon Infiltration for Additive Manufacturing
This invention introduces a novel method for enhancing the quality of metal parts produced via binder jet printing by infiltrating the intermediate "green body" with carbon and metal oxide microparticles. This technique significantly improves the densification and mechanical properties of sintered workpieces while offering superior control over grain structure and corrosion resistance compared to traditional mixing methods.
Description
The core technology utilizes a post-printing infiltration process to refine the microstructure of additively manufactured metal components. After a "green body" workpiece is printed using a metal powder and binder, it undergoes a debinding process to remove the binding agent, leaving behind a porous structure. This porous workpiece is then immersed in a liquid bath containing a controlled concentration of carbon microparticles and, optionally, metal oxides like chromium oxide. Sonication is applied to the bath to ensure deep and uniform penetration of these particles into the internal pores of the workpiece. During the subsequent sintering stage, the infiltrated carbon facilitates the formation of a liquid phase—specifically a eutectic liquid at grain boundaries for iron-based alloys, which acts as a "glue" to fill pores and promote densification. This targeted placement of carbon avoids the issues of non-uniform grain growth and porosity often found when carbon is mixed directly into the base powder. The addition of chromium oxide can further refine the process by reacting with excess carbon to prevent unwanted carbide precipitation, thereby maintaining the alloy's integrity and corrosion resistance.Applications
- Aerospace Components: Manufacturing high-strength, lightweight engine parts and structural elements using nickel-based alloys or titanium.- Automotive Engineering: Production of complex, wear-resistant gears and engine components from stainless steel and other ferrous alloys.
- Medical Devices: Creation of customized, corrosion-resistant implants and surgical tools.
- Industrial Tooling: Fabrication of high-performance molds, dies, and machine parts with intricate geometries.
- Energy Sector: Development of durable, high-temperature components for turbines and reactors using specialized metal alloys.
Advantages
- Enhanced Material Density: Achieves higher relative density in finished parts, reducing internal porosity that can lead to structural failure.- Superior Mechanical Properties: Improved densification and uniform grain size distribution lead to stronger and more reliable machine parts.
- Microstructural Control: Enables precise control over the formation of liquid phases during sintering, preventing the non-uniform grain growth typical of traditional additive manufacturing.
- Increased Corrosion Resistance: The optional infiltration of metal oxides helps mitigate carbide formation, preserving the material's ability to resist environmental degradation.
- Process Efficiency: Allows for lower sintering temperatures or shorter sintering times to reach desired density levels.