Composite Metal Powder Bed for Dense Alloy 3D Printing
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Solution Overview
Problem
Conventional additive manufacturing techniques for metallic parts, particularly alloys, often result in inadequate density and fail to meet ASTM specifications, leading to issues with porosity and mechanical properties.
Innovation Solution
Development of a highly flowable, dense powder composed of composite particles formed by blending elemental metal powders, spray-drying with a liquid, and plasma densification to create spherical particles with low interstitial contaminants, which are then used in a powder bed for additive manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional additive manufacturing techniques are used with metallic precursor materials, then the manufacturing process can be performed, but the resulting parts have inadequate density and fail to meet ASTM specifications
Solution Approach 1:
The patent applies preliminary action by pre-densifying the metallic powder particles through spray drying and plasma treatment before the additive manufacturing process. This preliminary densification ensures that the starting material has optimized density characteristics, which directly translates to higher density parts that meet ASTM specifications after printing.
Solution Approach 2:
The patent changes the physical and chemical parameters of the metallic powder through controlled oxidation, spray drying, and plasma treatment. These parameter changes transform the powder from a conventional state to a pre-densified state with optimized flowability and density, resolving the contradiction between manufacturability and part quality.
2Ease of operation
If metallic powder is used directly in additive manufacturing, then the process is simple, but the powder lacks flowability and uniformity required for reliable manufacturing
Solution Approach 1:
The patent introduces an intermediary treatment process involving spray drying and plasma exposure. This intermediary step acts as a mediator between the raw metallic powder and the final printing process, modifying the powder surface properties to achieve both excellent flowability and uniformity without compromising the metallic composition.
Solution Approach 2:
The patent modifies key parameters of the metallic powder including surface oxidation state, particle morphology, and flow characteristics through controlled thermal and plasma treatments. These parameter changes enable the powder to exhibit both superior flowability for easy handling and uniformity for precise manufacturing.
3Strength
If conventional metallic powders are used, then material handling is straightforward, but the parts exhibit porosity and reduced mechanical properties
Solution Approach 1:
The patent applies preliminary action by pre-densifying the powder particles and removing interstitial contaminants before manufacturing. This preliminary treatment reduces porosity at the source, ensuring that the final part has minimized voids and enhanced mechanical properties without requiring extensive post-processing.
Solution Approach 2:
The patent converts the potential harm of oxidation into a benefit by controlling the oxidation process to create a protective surface layer on the powder particles. This controlled oxidation, followed by plasma treatment, actually improves powder flowability and reduces harmful porosity in the final part, turning what could be a detrimental effect into a advantageous one.
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
The solution results in highly densified metallic parts with minimized shrinkage and improved thermal conductivity, achieving high mechanical properties and density suitable for ASTM standards.
Implementation Method 1
the slurry is spray-dried to produce flowable agglomerate particles
Implementation Method 2
The agglomerate is thermally heated (i.e., sintered) to remove any organic material and to densify the agglomerate
Implementation Method 3
the binder may be cured by, e.g., application of heat or light. After the printing is complete, the shaped, 3D part is made of the composite particles held together by the binder material. The shaped part may then be sintered to fuse the particles together and decompose (i.e., burn off) some or all of the binder material
Data Source
AI summary
Disclosed are methods for fabricating three-dimensional objects including providing a dry powder bed containing a powder comprising a plurality of substantially spherical composite particles each comprising a mixture and/or alloy of constituent metals, (i) the particles have a Hall flow rate ranging from approximately 1 s/50 g to approximately 25 s/50 g, and (ii) an outer surface of each of the particles comprises a plurality of grains, each grain being surrounded by a matrix, the grains comprising the first constituent metal, and the matrix comprising the one or more second constituent metals; forming a first layer of a shaped part; disposing a layer of the particles over the first layer of the shaped part; forming subsequent layers of the shaped part; and sintering the shaped part to form the three-dimensional object.