Additive-Manufactured Mo and W Components With Crack-Resistant Microstructure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Additive manufacturing of molybdenum (Mo) and tungsten (W) and their alloys faces challenges such as high defect frequency, low fracture toughness, and poor surface quality due to their high melting point, thermal conductivity, and low ductility, leading to issues like the balling effect, porosity, and intergranular cracking.
Innovation Solution
The use of an additive manufacturing process with a controlled oxygen content of less than or equal to 0.1 at% and a carbon content of greater than or equal to 0.08 at%, combined with selective laser or electron beam melting, to produce components with reduced defects, improved fracture toughness, and enhanced surface quality by optimizing the microstructure and grain boundary strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additive manufacturing process is used for Mo and W materials, then geometric design freedom is improved, but defect frequency increases due to high melting point and thermal conductivity
Solution Approach 1:
The patent applies parameter changes by optimizing the chemical composition parameters (oxygen content ≤0.1 at%, carbon content ≥0.08 at%) of the starting powder to resolve the contradiction between geometric design freedom and defect frequency. This compositional optimization modifies the material's behavior during additive manufacturing, reducing defects while maintaining the process's geometric advantages.
Solution Approach 2:
The patent employs an inert atmosphere principle by严格控制 the oxygen content in the starting powder to ≤0.1 at%, creating a controlled environment that prevents oxidation and reduces defects during the additive manufacturing process, thereby improving reliability without sacrificing geometric design freedom.
2Device complexity
If additive manufacturing process is used for Mo and W materials, then manufacturing complexity is reduced, but fracture toughness decreases due to balling effect and porosity
Solution Approach 1:
The patent changes the chemical parameters of the starting powder (oxygen ≤0.1 at%, carbon ≥0.08 at%) to minimize the balling effect and porosity formation during additive manufacturing. This parameter optimization directly improves fracture toughness while maintaining the simplicity of the additive manufacturing process.
Solution Approach 2:
The patent introduces carbon as an intermediary element (≥0.08 at%) that modifies the material behavior during processing, acting as a mediator to reduce the harmful balling effect and improve fracture toughness without adding significant manufacturing complexity.
3Ease of manufacture
If conventional powder metallurgy is used for Mo and W, then manufacturing simplicity is maintained, but geometric design freedom is limited
Solution Approach 1:
The patent maintains manufacturing simplicity by using a controlled powder metallurgy approach with optimized parameters (oxygen ≤0.1 at%, carbon ≥0.08 at%) that enables the material to be processed additively with reduced defects, thereby achieving both ease of manufacture and geometric design freedom.
4Quantity of substance
If starting powder with high oxygen content is used, then manufacturing cost is reduced, but grain boundary strength decreases leading to intergranular cracking
Solution Approach 1:
The patent changes the oxygen content parameter to ≤0.1 at%, which prevents grain boundary embrittlement and intergranular cracking. While this requires more careful powder production, it eliminates costly defects and rework, ultimately providing economic benefits through improved component reliability.
Solution Approach 2:
The patent applies preliminary anti-action by pre-controlling the oxygen content in the starting powder before manufacturing, preventing grain boundary weakening and intergranular cracking from occurring in the first place, rather than attempting to fix these issues after they arise.
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 significantly reduces the frequency of cracks, improves fracture toughness, and enhances surface quality by minimizing the balling effect and intergranular cracking, resulting in components with higher density and transcrystalline fracture behavior.
Implementation Method 1
selective laser melting (SLM), in which powder applied in layers is sintered locally using a laser beam
Implementation Method 2
selective electron beam melting (SEBM), in which powder applied in layers is locally melted
Implementation Method 3
local melting and solidification with high cooling rates, such as SLM, SEBM and LMD
Data Source
Figure 1~2b
Figure 3~4b
Figure 5a~5d
AI summary
The invention relates to a component comprising a plurality of individual powder particles, formed from Mo, a Mo-based alloy, W or a W-based alloy, which are melted together to form a solid structure via an additive manufacturing method using a high-energy beam, wherein the component has an oxygen-content that is lower than or equal to 0.1 at%. The invention also relates to an additive manufacturing method, wherein the powder is produced via the melting phase and has a carbon-content in the region of greater than or equal to 0.15 at%. The components according to the invention are free from cracks and are characterised by a high intergranular strength.