Refractory Metal AM Components With Nucleating Particulates
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Solution Overview
Problem
Molybdenum and tungsten components produced via additive manufacturing processes suffer from high defect frequency, low strength, poor fracture toughness, and low ductility due to issues like balling effect, intercrystalline cracking, and high oxygen content at grain boundaries, leading to poor weldability and processing difficulties.
Innovation Solution
Incorporation of particulates with a melting point above the matrix phase to act as crystallization nuclei, forming a fine-grained microstructure that reduces grain boundary weakness and enhances strength and toughness, while using precursor substances or alloying elements to manage oxygen content and reduce oxide formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additive manufacturing processes (SLM, SEBM) are used to produce molybdenum and tungsten components, then geometric design freedom and resource efficiency are improved, but defect frequency increases and mechanical properties deteriorate
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of the starting powder, specifically controlling oxygen content to below 500 ppm and adjusting alloying element concentrations. This resolves the contradiction by optimizing material parameters to eliminate defects while preserving the geometric design freedom inherent to additive manufacturing processes.
Solution Approach 2:
The patent employs composite materials by incorporating specific alloying elements (such as boron, silicon, or carbon) into the molybdenum or tungsten matrix. These composite structures refine the grain boundary characteristics and eliminate intercrystalline cracking, thereby reducing defect frequency while maintaining the geometric flexibility of additive manufacturing.
2Ease of manufacture
If beam-based additive manufacturing processes are used, then machining and forming tools are eliminated, but complex material-physical mechanisms cause poor component quality
Solution Approach 1:
The patent changes the thermal and compositional parameters of the additive manufacturing process by optimizing laser power density, scan speed, and powder composition. These parameter adjustments control the complex material-physical mechanisms during melting and solidification, ensuring high manufacturing precision while maintaining the advantage of eliminating traditional machining tools.
Solution Approach 2:
The patent replaces mechanical post-processing methods with optimized beam-based processing parameters and material composition control. By substituting mechanical intervention with precisely controlled thermal and chemical parameters, the process achieves high component quality directly from additive manufacturing without requiring subsequent machining or forming operations.
3Ease of manufacture
If conventional consolidation processes are used, then material processing is simpler, but geometric design freedom is limited
Solution Approach 1:
The patent uses composite material structures with controlled alloying elements that enable complex geometries to be manufactured with simplified process steps. The composite nature of the material allows direct additive manufacturing of complex shapes without requiring the complex tooling and multiple operations needed in conventional processes, thus achieving both geometric freedom and processing simplicity.
4Speed
If high cooling rates are used in beam-based processes, then local melting and solidification are achieved, but balling effect and intercrystalline cracking increase
Solution Approach 1:
The patent changes the compositional parameters of the starting powder by adding specific alloying elements (boron, silicon, carbon) that modify the solidification behavior. These compositional changes reduce surface tension and control grain boundary formation, thereby preventing balling effect and intercrystalline cracking even at high cooling rates inherent to beam-based additive manufacturing processes.
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 fine-grained microstructure significantly reduces defect frequency, improves strength, fracture toughness, and ductility, resulting in higher density and isotropic mechanical properties without compromising on component performance.
Implementation Method 1
selective laser beam melting (SLM) and selective electron beam melting (SEBM), in which powder applied layerwise is locally melted
Implementation Method 2
processes comprising local melting and solidification at high cooling rate
Implementation Method 3
Incorporation of particulates with a melting point above the matrix phase to act as crystallization nuclei, forming a fine-grained microstructure
Implementation Method 4
using precursor substances or alloying elements to manage oxygen content and reduce oxide formation
Data Source
AI summary
A component has a matrix phase composed of at least one material selected from the group molybdenum, a molybdenum-based alloy, tungsten, a tungsten-based alloy and a molybdenum-tungsten-based alloy. The component is manufactured using a laser or electron beam in an additive manufacturing process. The molybdenum content, the tungsten content or the total content of molybdenum and tungsten is more than 85 at %, and the component contains particulates having a melting point above the melting point of the matrix phase.