Precipitation-strengthened copper alloy and application thereof

Abstract

The invention is a precipitation-strengthened copper alloy, including the following components in percentage by weight: 80 wt %-95 wt % of Cu, 0.05 wt %-4.0 wt % of Sn, 0.01 wt %-3.0 wt % of Ni, 0.01 wt %-1.0 wt % of Si, and the balance of Zn and unavoidable impurities. According to the invention, the comprehensive performance of the alloy is improved by solution strengthening and precipitation strengthening; while the strength of the matrix is improved, the electrical conductivity of the alloy is hardly affected, the bending workability meets the requirements, and the stress relaxation resistance comparable to that of tin phosphor bronze is achieved. The comprehensive performance of the alloy of the invention is superior to that of the tin phosphor bronze C51900. Furthermore, the alloy of the invention is low in raw material cost, has obvious advantages in welding and plating.

Claims

1. A precipitation-strengthened copper alloy, comprising the following components in percentage by weight: 85.01 wt %-91.43 wt % of Cu, 0.05 wt %-4.0 wt % of Sn, 0.01 wt %-3.0 wt % of Ni, 0.01 wt %-1.0 wt % of Si, 5.32 wt %-19.93 wt % of Zn and unavoidable impurities, wherein matrix of the copper alloy contains NiSi phase precipitates, and in the matrix of the copper alloy the amount of NiSi phase precipitates having a particle diameter of 50 nm or less accounts for 75% or above of the total amount of the NiSi phase precipitates, wherein a X-ray diffraction intensity of a crystal face {111}, having a rolled surface within a range of 0<2θ<90°, of a strip of the copper alloy is denoted as I.sub.{111}, a X-ray diffraction intensity of a crystal face {200} is denoted as I.sub.{200}, a X-ray diffraction intensity of a crystal face {220} is denoted as I.sub.{220}, and a X-ray diffraction intensity of a crystal face {311} is denoted as I.sub.{311}, and I.sub.{111}, I.sub.{200}, I.sub.{220}, and I.sub.{311} satisfy: 0.5<(I.sub.{111}+I.sub.{220})/(I.sub.{200}+I.sub.{300}<10.

2. The precipitation-strengthened copper alloy according to claim 1, wherein the copper alloy further comprises the components in percentage by weight: 0.01 wt %-2.0 wt % of Co.

3. The precipitation-strengthened copper alloy according to claim 1, wherein the copper alloy further comprises the components in percentage by weight: 0.01 wt %-2.0 wt % of Fe and/or 0.001 wt %-1.0 wt % of P.

4. The precipitation-strengthened copper alloy according to claim 3, wherein the copper alloy further comprises the components in percentage by weight: at least one element of Mg, B, Re, Cr, and Mn in a total amount of not more than 2.0 wt %, wherein 0.005 wt %-1.5 wt % of Mg, 0.0005 wt %-0.3 wt % of B, 0.0001 wt %-0.1 wt % of Re, 0.01 wt %-1.5 wt % of Cr, and 0.001 wt %-0.8 wt % of Mn.

5. The precipitation-strengthened copper alloy according to claim 1, wherein a strip of the copper alloy has a yield strength of 600 MPa or above and an electrical conductivity of 20% IACS or above.

6. The precipitation-strengthened copper alloy according to claim 1, wherein a 90° bending workability of a strip of the copper alloy is as follows: a value of R/t in the GW direction is less than or equal to 1, and a value of R/t in the BW direction is less than or equal to 2.

7. The precipitation-strengthened copper alloy according to claim 4, wherein the copper alloy further comprises the components in percentage by weight: 0.01 wt %-2.0 wt % of Fe and/or 0.001 wt %-1.0 wt % of P.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a TEM photograph (10000×) of a strip sample according to Embodiment 1.

DESCRIPTION OF THE EMBODIMENTS

(2) With reference to the embodiments, the invention will be further described in detail below in connection with the drawing.

(3) Twenty embodiment alloys and two reference alloys (brass C28000 and tin phosphor bronze C51900) are selected, and the added elements are added to a melting furnace according to their respective contents, and the semi-continuous casting is carried out to obtain 170 mm×320 mm ingots at a casting temperature of 1150° C.

(4) Other major preparation process parameters are: Hot rolling: heating to 780° C., holding the temperature for 5 hours, and hot rolling to 16.5 mm; Face milling: milling upper and lower faces to 15 mm; Primary cold rolling: cold rolling to 2 mm from 15 mm; Primary aging: aging at 550° C., and holding the temperature for 6 hours; Secondary cold rolling: cold rolling to 0.35 mm from 2 mm; Secondary aging: aging at 380° C., and holding the temperature for 8 hours; Third cold rolling: cold rolling to 0.2 mm from 0.35 mm; Low-temperature annealing: annealing at 210° C., and holding the temperature for 6 hours, thus obtaining strip samples.

(5) For the prepared strip samples of 20 embodiment alloys and 2 reference alloys, mechanical properties, electrical conductivity, stress relaxation resistance and bending workability are respectively tested.

(6) The room temperature tensile test is carried out in accordance with GB/T 228.1-2010 Metallic Materials-Tensile Tests Part 1: Room Temperature Test Method on an electronic universal mechanical property test machine, using 12.5 mm wide strip end samples, with a tensile speed of 5 mm/Min.

(7) The electrical conductivity test is carried out in accordance with GB/T 3048.2-2007 Wires and Cables-Electrical Property test methods Part 2: Resistivity Tests for Metallic Materials, where the test instrument used is a ZFD microcomputer bridge DC resistance tester, with samples being 20 mm wide and 500 mm long.

(8) The stress relaxation resistance test is carried out in accordance with JCBA T309: 2004 Bending Stress Relaxation Test Methods for Copper and Copper Alloys, where samples which are 10 mm wide and 100 mm long are taken parallel to the rolling direction, the initial loading stress value is 50% of 0.2% yield strength, the test temperature is 150° C., the test time is 1000 h.

(9) The bending property test is carried out on a bending test machine in accordance with GBT 232-2010 Metallic Materials-Bending Test Methods, with samples being 5 mm wide and 50 mm long.

(10) The composition and property test results of Embodiments and references are shown in Table 1. A TEM photograph of the strip sample in Embodiment 1 is shown in FIG. 1.

(11) TABLE-US-00001 TABLE 1 Composition and property test results of Embodiments and references The percentage of NiSi phase precipitates having a particle diameter of 50 Element content/wt % nm or less in the total Property Optional amount of the NiSi Yield No. Cu Sn Ni Si Zn element phase precipitates/% strength/MPa Embodiment 1 80.11 1.52 1.33 0.33 Balance 89 657 Embodiment 2 85.01 0.49 1.01 0.22 83 621 Embodiment 3 86.54 0.73 1.68 0.54 0.21Mg 95 633 Embodiment 4 87.75 2.09 1.61 0.36 76 686 Embodiment 5 85.82 0.35 1.66 0.53 84 629 Embodiment 6 83.44 2.28 2.05 0.44 91 721 Embodiment 7 82.06 1.02 1.28 0.31 87 657 Embodiment 8 88.18 1.59 0.87 0.21 0.05Cr 91 642 Embodiment 9 89.35 0.87 2.23 0.61 87 622 Embodiment 10 91.52 1.97 1.79 0.51 78 655 Embodiment 11 86.02 2.52 1.76 0.39 79 625 Embodiment 12 82.93 0.51 1.04 0.11 76 654 Embodiment 13 85.55 1.53 1.92 0.43 84 674 Embodiment 14 90.22 0.63 1.52 0.36 91 636 Embodiment 15 93.79 3.61 1.23 0.32 87 646 Embodiment 16 94.89 1.26 0.82 0.83 91 643 Embodiment 17 88.85 2.69 1.57 0.31 89 745 Embodiment 18 88.07 1.22 2.62 0.58 0.001B 83 736 Embodiment 19 91.43 0.08 2.53 0.48 0.16Mg 95 667 Embodiment 20 86.65 1.51 3.71 0.36 0.01Re 76 643 C28000 61.8  Balance 430 C51900 Balance 5.84 0.12 612 Property Electrical Stress relaxation Bending conductivity/ resistance 90°, BW, No. Ductility/% % IACS (Residual stress/%) R/t Embodiment 1 5 25.7 76 2 Embodiment 2 5 31.6 80 1 Embodiment 3 5 29.8 83 1 Embodiment 4 3 24.5 78 2 Embodiment 5 5 30.9 79 2 Embodiment 6 3 23.1 76 2 Embodiment 7 3 26.9 81 2 Embodiment 8 3 24.9 75 1 Embodiment 9 4 30.1 81 1 Embodiment 10 4 31.3 82 2 Embodiment 11 4 25.9 83 1 Embodiment 12 3 27.7 75 2 Embodiment 13 3 24.6 82 2 Embodiment 14 3 35.7 80 1 Embodiment 15 4 21.7 76 1 Embodiment 16 4 23.2 81 2 Embodiment 17 3 25.7 72 2 Embodiment 18 3 23.8 75 2 Embodiment 19 5 36.8 83 1 Embodiment 20 3 28.6 81 2 C28000 5 23.2 32 4 C51900 4 14 64 2