Additive Fe-Co Magnetic Elements With Controlled Microstructure
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Solution Overview
Problem
Soft magnetic alloys like Fe-Co-V alloys, used in applications such as Hall thrusters and motors, are brittle and difficult to machine, and their magnetic properties degrade during processing, limiting their effectiveness and reliability.
Innovation Solution
The method involves additive manufacturing using a powderized feedstock of magnetic alloys, specifically Fe-Co alloys like Hiperco® 50, with controlled thermal energy deposition and heat treatment processes to achieve high density and tailored magnetic and mechanical properties, including varying grain structures and compositional gradients, to enhance magnetic saturation, permeability, and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional machining methods are used on soft magnetic alloys, then the material can be processed, but the magnetic properties deteriorate strongly
Solution Approach 1:
The patent replaces conventional mechanical machining with additive manufacturing technology. The magnetic elements are built layer-by-layer using melted powder material, eliminating mechanical contact and tooling that cause magnetic property deterioration. This substitution of manufacturing methodology resolves the contradiction by achieving both manufacturability and magnetic property preservation.
Solution Approach 2:
The patent controls and optimizes additive manufacturing parameters including energy density (30-60 J/mm²), layer thickness (25-75 micrometers), and build temperature to achieve high density (≥98%) while preserving magnetic properties. By precisely controlling these parameters, the process achieves both ease of manufacture and reliability of magnetic characteristics.
2Strength
If mechanical strengthening is applied to improve mechanical properties, then strength increases, but magnetic properties deteriorate
Solution Approach 1:
The patent performs preliminary action by optimizing the additive manufacturing process parameters during fabrication to achieve the desired balance between mechanical strength and magnetic properties. The process parameters are predetermined and controlled to produce the required microstructure and density, eliminating the need for subsequent mechanical strengthening that would harm magnetic properties.
Solution Approach 2:
The patent uses parameter changes in the additive manufacturing process, specifically controlling energy density (30-60 J/mm²) and heat treatment conditions, to achieve both adequate mechanical strength and preserved magnetic properties simultaneously, rather than needing to apply mechanical strengthening afterward.
3Ease of manufacture
If additive manufacturing is used with conventional energy density, then manufacturing is simpler, but density is insufficient and magnetic properties are poor
Solution Approach 1:
The patent applies parameter changes by optimizing the energy density to a specific range (30-60 J/mm²) and controlling layer thickness (25-75 micrometers) to achieve high density (≥98%). These precise parameter controls enable both manufacturing simplicity through additive manufacturing and high manufacturing precision in terms of density and magnetic properties.
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 enables the production of magnetic elements with improved mechanical and magnetic properties, achieving densities above 98% and magnetic flux densities of at least 2 A/m, with reduced brittleness and enhanced reliability, surpassing state-of-the-art performance in similar machined parts.
Implementation Method 1
additively manufacturing a magnetic element having a density of at least 98% from a plurality of successive layers of deposited powderized feedstock using a thermal energy source having a specific energy of deposition between about 30 and 60 J/mm2
Implementation Method 2
annealing the magnetic element in a vacuum atmosphere at a temperature between about 830° C. and 875° C. for at least 4 hours±10 minutes
Implementation Method 3
quenching the annealed magnetic element to at least below 500° C.±20° C. at a cooling rate of at least 80° C./hour±10° C./hour in a vacuum atmosphere
Data Source
AI summary
Elements formed from magnetic materials and their methods of manufacture are presented. Magnetic materials include a magnetic alloy material, such as, for example, an Fe-Co alloy material (e.g., the Fe-Co-V alloy Hiperco-50(R)). The magnetic alloy materials may comprise a powdered material suitable for use in additive manufacturing techniques, such as, for example direct energy deposition or laser powder bed fusion. Manufacturing techniques include the use of variable deposition time and energy to control the magnetic and structural properties of the materials by altering the microstructure and residual stresses within the material. Manufacturing techniques also include post deposition processing, such as, for example, machining and heat treating. Heat treating may include a multi-step process during which the material is heated, held and then cooled in a series of controlled steps such that a specific history of stored internal energy is created within the material. Magnetic elements may include, for example, motors, generators, solenoids and swtiches, sensors, transformers, and hall thrusters, among other elements.