Special round copper wire with bending resistance

Abstract

The utility model discloses a kind of anti-bending special round copper wires, including coaxially arranged core layer, transition layer and protective layer, and with the following structural features: the core layer surface is equipped with continuous spiral microgroove;The transition layer covers core layer and fills the microgroove and forms mechanical interlocking projection;The outer surface of the protective layer is distributed with nano-scale pit structure.The interlayer peeling resistance of the utility model: swallow-tail microgroove and interlocking projection structure make interlayer peeling force improve compared with traditional plane combination, interface is not delaminated after being bent for many times;Dynamic stress optimization: conical frustum gradient pore buffer layer makes bending stress concentration coefficient drop;Fatigue life doubling: nano pit reduces crack propagation rate through crack deflection effect, and 90 ° repeated bending life improves compared with traditional copper wire.

Description

Technical Field

[0001] This utility model belongs to the field of round copper wire technology, and particularly relates to special round copper wire with bending resistance. Background Technology

[0002] Existing round copper wires have defects under dynamic bending conditions:

[0003] Delamination: Traditional copper-clad steel wires use a planar bonding interface, and shear stress during bending causes delamination;

[0004] When a homogeneous cross-section wire is bent, the surface stress can reach three times that of the core, causing the coating to crack. Utility Model Content

[0005] This utility model addresses the problems existing in the prior art by proposing the following technical solution:

[0006] The special round copper wire with bending resistance includes a core layer, a transition layer, and a protective layer arranged coaxially, and has the following structural features:

[0007] The surface of the core layer is provided with continuous spiral microgrooves;

[0008] The transition layer covers the core layer and fills the microgroove to form a mechanically interlocking protrusion;

[0009] The outer surface of the protective layer has a nanoscale pit structure.

[0010] As a preferred embodiment of the above technical solution, the cross-section of the microgroove is dovetail-shaped, and the width of the groove bottom is narrower than the width of the groove opening.

[0011] As a preferred embodiment of the above technical solution, a gradient porosity buffer layer is provided between the transition layer and the protective layer, wherein the porosity of the buffer layer gradually changes from 30% near the transition layer side to 60% near the protective layer side.

[0012] As a preferred embodiment of the above technical solution, the pores of the gradient pore buffer layer are frustoconical, with the larger end facing the protective layer.

[0013] The beneficial effects of this utility model are as follows:

[0014] In this application,

[0015] Interlayer peel resistance: The dovetail-shaped microgrooves and interlocking protrusions enhance the interlayer peel resistance compared to traditional planar bonding, and the interface remains undelaminated after multiple bends;

[0016] Dynamic stress optimization: The frustum-shaped gradient pore buffer layer reduces the bending stress concentration factor;

[0017] Increased fatigue life: The nano-dimples reduce the crack propagation rate through crack deflection effect, and the fatigue life is improved compared with traditional copper wires after repeated 90° bending. Attached Figure Description

[0018] Figure 1 The diagram shown is a frontal view of the internal structure of an embodiment of the present invention.

[0019] Legend:

[0020] 1. Core layer; 101. Microgroove; 2. Transition layer; 201. Protrusion; 3. Protective layer; 301. Pits; 4. Gradient pore buffer layer. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments.

[0022] Example 1 (φ1.5mm wire):

[0023] like Figure 1 As shown in the embodiment of this utility model, the bend-resistant special round copper wire includes a core layer 1. First, the core layer 1 is processed with microgrooves: a high carbon steel wire with a diameter of φ0.68mm is selected, and a continuous microgroove 101 with a helical angle of 60°±1° is etched on its surface using an ultraviolet laser with a wavelength of 355nm and a pulse width of 15ns.

[0024] The depth of the microgroove 101 is controlled at 35μm±2μm, the pitch is 0.16mm±0.01mm, and the cross-section is machined into a dovetail shape (groove bottom width 40μm, groove opening width 88μm, forming a locking ratio of 1:2.2).

[0025] Subsequently, the transition layer 2 is applied: In an argon-protected environment, the oxygen-free copper strip is heated to 350℃±10℃ and 15MPa pressure is applied to hot press the core layer 1, so that the molten copper completely fills the microgroove 101 and solidifies to form a barbed interlocking protrusion 201. The measured height of the protrusion 201 is 42μm±3μm, and the filling rate is ≥98%.

[0026] Next, a gradient porosity buffer layer 4 was prepared: the current density was linearly adjusted from 0.5 A / dm³ using a pulsed electrodeposition process. 2 Increased to 2.0A / dm 2 A gradient pore buffer layer 4 is generated on the surface of the transition layer 2, with the porosity gradually changing from 30% at the interface to 60% at the outer surface. The pore morphology is frustoconical (the large end diameter is 500nm±50nm facing the protective layer, the small end diameter is 300nm±30nm, and the cone angle is 16°±0.5°).

[0027] Finally, protective layer 3 is applied: using an energy density of 2J / cm³. 2Nanosecond lasers were used to etch nano-pits (301) on the outer surface of buffer layer 4, controlling the pit diameter to be 1.2 μm ± 0.2 μm, the depth to be 0.5 μm ± 0.1 μm, and the density to be 5 × 10⁻⁶. 5 pcs / mm 2 The distribution uniformity is >90%.

[0028] Example 2 (φ2.0mm wire)

[0029] The diameter of core layer 1 was increased to φ0.95mm, and the parameters of microgroove 101 were adjusted to a depth of 45μm±3μm and a pitch of 0.20mm±0.01mm (dovetail groove bottom width 50μm, groove opening width 110μm, maintaining a 1:2.2 ratio).

[0030] The porosity gradient of the gradient pore buffer layer 4 is expanded from 25% to 65%, and the cone angle is increased to 17°±0.5° to accommodate greater bending deformation.

[0031] The density of the 301 surface pit structure has been increased to 8×10. 5 pcs / mm 2 To enhance crack suppression capabilities.

[0032] Working principle

[0033] Shear force transmission mechanism: During bending, the interlayer shear force τ is borne by the 55° inclined sidewall of the dovetail groove (mechanical model: τ=F / (A·sin55°)), and the effective bearing area is increased by 220% under the same load. The barbed interlocking protrusions (201) form a mechanical self-locking mechanism to prevent interlayer slippage.

[0034] Stress gradient dissipation principle: The frustum-shaped pores constitute a nonlinear stiffness material. When the porosity P increases from 30% to 60%, the elastic modulus E decreases from 174 GPa to 72 GPa (constitutive relation: σ=E(P)·ε);

[0035] The 60% pore region absorbs 42% of the strain energy through collapse, significantly reducing the peak stress.

[0036] Crack suppression mechanism: The surface nano-pits 301 produce a triple effect:

[0037] A compressive residual stress field with an average value of -125 MPa was formed (verified by X-ray diffraction).

[0038] Forced crack deflection propagation resulted in a path growth rate of 38% (metallographic observation);

[0039] The stress intensity factor ΔK1 at the crack tip was reduced by 37% (calculated using the Irwin model).

[0040] The above embodiments are only used to illustrate the technical solution of this utility model, and are not intended to limit it.

Claims

1. A special round copper wire resistant to bending, characterized in that, It includes a core layer (1), a transition layer (2), and a protective layer (3) arranged coaxially, and has the following structural features: The surface of the core layer (1) is provided with continuous spiral microgrooves (101); The transition layer (2) covers the core layer and fills the microgroove to form a mechanically interlocking protrusion (201); The outer surface of the protective layer (3) is covered with nanoscale pit structures (301).

2. The special bend-resistant round copper wire according to claim 1, characterized in that, The cross-section of the microgroove (101) is dovetail-shaped, and the width of the bottom of the groove is narrower than the width of the opening.

3. The special bend-resistant round copper wire according to claim 1, characterized in that, A gradient porosity buffer layer (4) is provided between the transition layer (2) and the protective layer (3), the porosity of which gradually changes from 30% near the transition layer to 60% near the protective layer.

4. The special bend-resistant round copper wire according to claim 3, characterized in that, The pores of the gradient pore buffer layer (4) are frustoconical, with the larger end facing the protective layer (3).

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