Metallic Alloy Wire Feedstock for Dense HEA 3D Printing
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Solution Overview
Problem
The additive manufacturing of high-entropy alloys (HEAs) and multi-principal element alloys (MPEAs) faces challenges such as difficulty in fabrication due to high strength and limited ductility, as well as issues like porosity, cracking, and excessive oxygen content in metallic precursor materials, leading to sparking, blistering, and insufficient density in fabricated parts.
Innovation Solution
The development of metallic wires for additive manufacturing, where powders of alloy constituents are processed to minimize oxygen and volatile species through techniques like hydride/dehydride processes and plasma densification, forming wires with a combination of spherical and non-spherical particles to reduce inter-particle space and trapped volatile species, which are then melted to form homogeneous three-dimensional parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If metallic precursor materials with significant oxygen and volatile species are used for additive manufacturing, then the manufacturing process can proceed, but the resulting parts exhibit porosity, cracking, material splatter, and insufficient density
Solution Approach 1:
The patent applies preliminary action by treating the metal powders with hydrogen before wire fabrication to remove oxygen and volatile species. The hydrogen treatment reduces oxygen content to below 300 ppm and volatile species to below 100 ppm in the final wire, preventing porosity and cracking in the manufactured parts while maintaining additive manufacturing processability
Solution Approach 2:
The patent changes the chemical composition parameters of the precursor materials through controlled hydrogen treatment. By adjusting hydrogen exposure conditions, the oxygen content is reduced to below 300 ppm and volatile species to below 100 ppm, transforming the material from unsuitable (high oxygen) to suitable (low oxygen) for high-quality additive manufacturing
2Productivity
If metal powders with high oxygen content are melted during additive manufacturing, then the manufacturing process can continue, but sparking and blistering occur during melting
Solution Approach 1:
The patent applies preliminary action by performing hydrogen treatment on metal powders before wire fabrication and additive manufacturing. This pre-treatment removes oxygen and volatile species that would cause sparking and blistering during melting, allowing continuous manufacturing without interruptions from harmful effects
Solution Approach 2:
The patent converts the potentially harmful interaction between oxygen and molten metal (which causes sparking) into a beneficial process by using controlled hydrogen exposure. The hydrogen selectively removes oxygen from the powder before manufacturing, transforming what would be a harmful reaction into a controlled purification step
3Stability of the object's composition
If conventional metal powders are used to fabricate HEAs and MPEAs, then the alloy composition can be achieved, but diffusion is slow and homogenization is difficult in bulk quantities
Solution Approach 1:
The patent applies segmentation by dividing the bulk material into fine powder particles before alloying. The metal powders are treated with hydrogen at the particle level to ensure uniform composition, and then fabricated into wire. This segmented approach allows complete homogenization of the alloy composition before final forming, overcoming the slow diffusion in bulk materials
Solution Approach 2:
The patent changes the physical state parameter from bulk to fine powder, dramatically increasing the surface area to volume ratio. This parameter change enables complete diffusion and homogenization of alloying elements throughout the material during hydrogen treatment, achieving uniform composition that would be impossible in bulk quantities
4Stability of the object's composition
If additive manufacturing uses small melt pools for HEA fabrication, then homogenized alloy composition can be achieved, but the process requires precursor materials with very low volatile species content
Solution Approach 1:
The patent applies preliminary action by performing hydrogen treatment on metal powders before wire fabrication. This pre-treatment ensures the precursor wire contains less than 300 ppm oxygen and less than 100 ppm volatile species, meeting the stringent requirements for small melt pool additive manufacturing while maintaining alloy homogeneity
Solution Approach 2:
The patent provides beforehand cushioning by creating a buffer through hydrogen treatment that removes potential contaminants before the additive manufacturing process. The treated wire serves as a cushioned starting material that prevents composition instability during the sensitive small melt pool process
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach results in the production of high-density, crack-free, and homogenous three-dimensional parts with improved machinability and reduced porosity, effectively addressing the challenges of fabricating HEAs and MPEAs in additive manufacturing.
Implementation Method 1
The powders are formed utilizing one or more techniques that minimize or substantially reduce the amount of oxygen and other volatile elements within the powders. For example, various powders may be formed and/or treated via a hydride/dehydride process, plasma densification, and/or plasma atomization
Implementation Method 2
various powders may be formed and/or treated via a hydride/dehydride process
Implementation Method 3
the tip of the wire is melted by, e.g., an electron beam or a laser
Implementation Method 4
the tip of the wire is melted by, e.g., an electron beam or a laser
Implementation Method 5
the small melt pool of material utilized at any point in time during an additive manufacturing process may result in small molten volumes of substantially homogenous alloy material that cool at a rate sufficient to stabilize the homogenized composition of the alloy
Data Source
AI summary
In various embodiments, additive manufacturing is utilized to fabricate three-dimensional metallic parts using metallic alloy wire as a feedstock material.