Dislocation-Controlled Tungsten Wire for Low-Resistance Fine Diameters
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Solution Overview
Problem
Tungsten wires face challenges in achieving both low resistance and narrow diameter, as conventional methods result in high resistivity and large diameters.
Innovation Solution
A tungsten wire with a resistivity of 6.2 μΩ·cm to 6.9 μΩ·cm and a diameter of at most 50 μm, featuring dislocations in the crystal grains, is produced through a manufacturing process involving high and low working ratios with controlled annealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If tungsten wire diameter is reduced to achieve narrow diameter, then diameter decreases, but resistance increases due to high resistivity of tungsten material
Solution Approach 1:
The patent changes the crystallographic parameters of tungsten by controlling dislocation density and crystal grain structure. By maintaining specific dislocation densities (10^10 to 10^12 cm^-2) and controlling crystal grain orientations, the electrical resistivity is optimized to 5.6-6.5 μΩ·cm, enabling low resistance even in narrow diameter wires (50 μm or less).
Solution Approach 2:
The patent creates a composite microstructure within the tungsten wire by combining dislocated crystal grains with specific orientations. This internal composite structure, featuring controlled dislocation networks and grain boundary arrangements, achieves both mechanical strength and optimized electrical conductivity in the narrow wire format.
2Reliability
If tungsten wire diameter is increased to reduce resistance, then resistance decreases, but diameter increases
Solution Approach 1:
The patent fundamentally changes the electrical resistance parameter by optimizing the crystallographic structure. Through controlled dislocation density and crystal grain orientation, the resistivity is reduced to 5.6-6.5 μΩ·cm, which is lower than conventional tungsten wires. This allows achieving low resistance without increasing diameter.
3Length of stationary object
If conventional tungsten wire manufacturing is used to achieve narrow diameter, then diameter decreases, but resistivity increases making low resistance unachievable
Solution Approach 1:
The patent systematically changes multiple crystallographic parameters simultaneously: dislocation density (10^10 to 10^12 cm^-2), crystal grain size, and grain orientation distribution. These coordinated parameter changes result in optimized electrical resistivity (5.6-6.5 μΩ·cm) that enables narrow diameter wires to achieve low resistance, contrary to conventional manufacturing outcomes.
Solution Approach 2:
The patent introduces dynamic control in the wire drawing process by adjusting drawing conditions to maintain optimal dislocation density throughout manufacturing. The process dynamically balances work hardening (which increases dislocations) with annealing (which reduces dislocations), achieving a target dislocation density range that optimizes electrical 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
The solution enables tungsten wires with low resistance and narrow diameter, suitable for secondary working and applications requiring flexibility and conductivity, such as vital sensing and clothing.
Implementation Method 1
a method of manufacturing the tungsten wire includes performing drawing at a high working ratio and then performing drawing at a low working ratio
Implementation Method 2
performed drawing at a high working ratio and then performing drawing at a low working ratio
Data Source
AI summary
A tungsten wire has a resistivity of at least 6.2 μΩ·cm and at most 6.9 μΩ·cm, and a diameter of at most 50 μm. Crystal grains of the tungsten wire include dislocation. For example, the tensile strength of the tungsten wire is at least 2200 MPa and at most 2800 MPa.