Core-Shell Alloy Powder for Uniform In-Situ Nano-Precipitates
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Solution Overview
Problem
Conventional methods for producing oxide or nitride dispersion strengthened alloys through mechanical ball milling result in undesirable coarsening, agglomeration, and non-uniform distribution of nano-sized particles during additive manufacturing, leading to adverse effects on component properties and high production costs.
Innovation Solution
The use of core-shell structured alloy powders with a metal alloy core and oxygen or nitrogen-rich shell, processed via laser or electron beam powder bed additive manufacturing, allows for in-situ formation of uniformly distributed nano-sized oxide or nitride precipitates during manufacturing and subsequent heat treatment, optimizing their size, distribution, and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If mechanical ball milling is used to mix nano-sized oxide or nitride particles with metallic alloy powders, then the particles can be combined, but the particles undergo coarsening, agglomeration, and non-uniform distribution during additive manufacturing
Solution Approach 1:
The patent applies preliminary action by pre-coating the metal alloy powder cores with oxygen or nitrogen-rich shells before additive manufacturing. This pre-preparation ensures that when the powder is exposed to laser or electron beam heating, the reactive shells immediately form uniform nano-sized oxide or nitride precipitates in-situ, preventing the coarsening and agglomeration that occurs when pre-mixed particles are used. The preliminary coating action resolves the distribution and stability issues.
Solution Approach 2:
The patent replaces the mechanical ball milling system with a chemical/physical in-situ formation system. Instead of mechanically mixing pre-formed nano-particles with metal powders (which leads to agglomeration), the invention uses laser or electron beam energy to trigger chemical reactions between the oxygen/nitrogen-rich shells and metal cores, forming precipitates in-situ during additive manufacturing. This substitution eliminates the mechanical handling that causes particle degradation.
2Ease of manufacture
If conventional ball milling processes are used to produce powder mixtures, then nano-sized particles can be mixed with alloy powders, but the process is time consuming and expensive
Solution Approach 1:
The patent merges the powder mixing step with the additive manufacturing process itself. Instead of separately mixing powders via ball milling and then performing additive manufacturing, the invention combines these operations by using the laser or electron beam energy during additive manufacturing to simultaneously form the oxide/nitride precipitates in-situ from the coated powder cores. This merging eliminates the time-consuming ball milling step while maintaining product quality.
Solution Approach 2:
The patent extracts and eliminates the unnecessary ball milling step from the manufacturing process. By designing the powder with pre-applied oxygen or nitrogen-rich shells, the invention removes the need for mechanical mixing and separate particle formation steps. The additive manufacturing process alone suffices to create the final precipitation-strengthened alloy, significantly reducing production time and cost.
3Strength
If pre-processed nano-sized oxide or nitride particles are used in additive manufacturing, then components can be formed, but the particles form large, agglomerated, and non-uniform structures that adversely affect physical properties
Solution Approach 1:
The patent applies parameter changes by controlling the oxygen or nitrogen content in the shell layer of the coated powder cores. By adjusting the thickness and composition of the reactive shell, the process optimizes the in-situ formation of nano-sized precipitates during additive manufacturing. This parameter control ensures uniform, fine-dispersed precipitates rather than large agglomerates, maintaining both particle size precision and mechanical strength.
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 components with enhanced mechanical properties, irradiation resistance, and reduced manufacturing time and cost, while eliminating the need for pre-existing oxides or nitrides, ensuring stable and uniform nano-sized precipitates are formed within the metal alloy matrix.
Implementation Method 1
additively manufacturing the alloy component using a laser or electron beam based powder bed process
Implementation Method 2
additively manufacturing the alloy component using a laser or electron beam based powder bed process
Implementation Method 3
The core-shell structured alloy powder comprises an alloy powder core and an oxygen or nitrogen rich shell disposed on at least a portion of the alloy powder core
Implementation Method 4
The core-shell structured alloy powder comprises an alloy powder core and an oxygen or nitrogen rich shell disposed on at least a portion of the alloy powder core
Data Source
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AI summary
A core-shell structured alloy powder for additive manufacturing, an additively manufactured precipitation dispersion strengthened alloy component, and a method for additively manufacturing the component are provided. The alloy powder comprises a plurality of particles, where one or more of the plurality of particles comprise an alloy powder core and an oxygen or nitrogen rich shell disposed on at least a portion of the alloy powder core. The alloy powder core comprises an alloy constituent matrix with one or more reactive elements, where the reactive elements are configured to react with oxygen, nitrogen, or both. The alloy constituent matrix comprises stainless steel, an iron based alloy, a nickel based alloy, a nickel-iron based alloy, a cobalt based alloy, a copper based alloy, an aluminum based alloy, a titanium based alloy, or combinations thereof. The alloy constituent matrix comprises reactive elements present in a range from about 0.01 weight percent to 10 weight percent of a total weight of the alloy powder.