Low-Impurity Refractory Wire for Crack-Free Metal Additive Parts
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Solution Overview
Problem
Additive manufacturing of metallic parts faces challenges such as sparking, blistering, splattering, porosity, cracking, and insufficient density due to the melting of metallic precursor materials, which are exacerbated by the presence of volatile impurities.
Innovation Solution
The development of wires with reduced gaseous and volatile impurities, such as oxygen, sodium, and phosphorus, made from refractory metals like niobium, tantalum, rhenium, tungsten, and molybdenum, fabricated through arc melting in a vacuum or inert ambient, minimizing impurities and enabling successful additive manufacturing with minimal defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional metallic precursor materials are used in additive manufacturing, then the manufacturing process can be performed, but the resulting parts exhibit porosity, cracking, and insufficient density
Solution Approach 1:
The wire is pre-fabricated with minimized volatile impurities through arc melting in vacuum or inert atmosphere before the additive manufacturing process. This preliminary purification action ensures that when the wire is melted during printing, there are minimal volatile elements to cause porosity, blistering, or cracking, thereby achieving high-density, crack-free parts
Solution Approach 2:
The invention changes the chemical composition parameters of the wire material by reducing volatile impurities (oxygen, sodium, magnesium, phosphorus, sulfur, potassium, calcium, antimony) to concentrations below 20 ppm, and preferably below 1 ppm. This parameter change in material purity directly resolves the contradiction by enabling high part density and integrity
2Productivity
If metallic precursor materials containing volatile impurities are melted during additive manufacturing, then the layer-by-layer fabrication can proceed, but sparking, blistering, and splattering occur
Solution Approach 1:
The wire is fabricated in an inert atmosphere (vacuum or inert gas) during the arc melting process, which prevents oxidation and minimizes volatile impurity formation. This inert environment control eliminates the harmful sparking and splattering that would otherwise occur when volatile impurities are present during subsequent additive manufacturing operations
Solution Approach 2:
The invention converts the potential harm of volatile impurities into a benefit by using arc melting in vacuum/inert atmosphere to deliberately remove these impurities before printing. The harmful volatile elements become the target of removal, and their absence then enables clean, spark-free manufacturing with high productivity
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 approach results in high-density, crack-free metallic parts with densities greater than 96% of theoretical density, free from porosity and cracking, and suitable for various applications including 3D printing and wire-fed welding.
Implementation Method 1
the precursor wire is fabricated, at least partially, via arc melting in a vacuum or a substantially inert ambient
Implementation Method 2
the tip of the wire is melted by, e.g., an electron beam or a laser
Implementation Method 3
the tip of the wire is melted by, e.g., an electron beam or a laser
Implementation Method 4
arc melting in a vacuum or a substantially inert ambient
Implementation Method 5
arc melting in a vacuum or a substantially inert ambient
Data Source
AI summary
In various embodiments, three-dimensional layered metallic parts are substantially free of gaps between successive layers, are substantially free of cracks, and have densities no less than 97% of the theoretical density of the metallic material.