Microstructure and properties of a novel Cu–3Ti–0.1Mg–0.05B–0.05 La alloy with high strength and conductivity
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摘要: 采用真空熔鑄和冷開坯工藝，通過優化形變熱處理工藝，調控基體晶粒尺寸、第二相的析出及分布狀態，制備出綜合性能優異的Cu?3Ti?0.1Mg?0.05B?0.05La合金。結果表明，經過400 ℃/2 h一次時效處理后，Cu?3Ti?0.1Mg?0.05B?0.05La合金的顯微硬度可達356 HV，此時導電率為14.5%IACS。透射電鏡分析表明，Cu?3Ti?0.1Mg?0.05B?0.05La合金第二相的析出演變規律為富Ti相→顆粒狀β′-Cu4Ti相→顆粒狀β′-Cu4Ti相+片層狀β-Cu4Ti相→片層狀β-Cu4Ti相，其中顆粒狀β′-Cu4Ti相是最重要的強化相，片層狀β-Cu4Ti相會導致合金強度下降，但可以提高導電率。采用二次時效能夠進一步優化Cu?3Ti?0.1Mg?0.05B?0.05La合金的綜合性能，在合金強度基本不變的條件下，顯著提升了合金的導電率。450 ℃/8 h一次時效+50%冷軋+400 ℃/1 h二次時效處理后合金的顯微硬度和導電率分別達到了341 HV和20.5%IACS。Abstract: The Cu–Ti alloy has similar mechanical properties and electrical conductivity to the Cu–Be alloy. It also exhibits excellent high-temperature properties and stress relaxation resistance. Therefore, it has emerged as a promising material to replace the toxic Cu–Be alloy. With the technological advances, the new generation of connector materials put forward higher requirements for performance, such as strength over 1000 MPa and conductivity over 15%IACS. However, it is difficult to obtain Cu–Ti alloys with such high strength and conductivity. An effective way is to increase the aging temperature or prolong the holding time of the alloy. When the strength of the alloy is reduced, the increase in cost is inevitable. The refining of grains or the regulation of size and distribution of precipitates has proved more effective, which is also true for Cu–Ti alloys. Currently, the refined grain size is still 10–50 μm achieved through a series of common processing methods, including hot rolling, solid solution, and cold rolling. Therefore, the improvement of strength and conductivity is limited for the Cu–Ti alloy. This paper provides a preparation method for synchronously improving the strength and conductivity of the Cu–Ti alloy. The Cu–3Ti–0.1Mg–0.05B–0.05La alloy with an ultra-fine grain structure is obtained via the vacuum casting and cold billet opening. The secondary aging process is used to adjust the size and distribution of the second phase to obtain a Cu–Ti alloy strip with high strength and good conductivity. The results show that the Cu–3Ti–0.1Mg–0.05B–0.05La alloy displays the maximum microhardness of 356 HV and a conductivity of 14.5%IACS after aging at 400 ℃/2 h. The relationship between the second phase precipitation and properties of the Cu–3Ti–0.1Mg–0.05B–0.05La alloy was analyzed using TEM (Transmission electron microscope). The evolution of the second phase is the Ti-rich phase → the granular phase β′-Cu4Ti phase → the granular β′-Cu4Ti phase + lamellar β-Cu4Ti phase → the lamellar β-Cu4Ti phase. The granular β′-Cu4Ti phase is the most important strengthening phase; the lamellar β-Cu4Ti phase can decrease the strength of the alloy but increase the conductivity. The comprehensive properties of Cu–3Ti–0.1Mg–0.05B–0.05La alloy can be further optimized by the secondary aging process. The microhardness and electrical conductivity of the Cu–3Ti–0.1Mg–0.05B–0.05La alloy reach 341 HV and 20.5%IACS after the primary aging at 450 ℃/8 h + 50% cold rolling + secondary aging at 400 ℃/1 h.
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圖 1 合金組織形貌. (a) 鑄態金相組織; (b) 鑄態SEM組織; (c) 800 ℃/24 h均勻化后SEM組織; (d) 820 ℃/2 h固溶后金相組織
Figure 1. Microstructure of the alloy: (a) metallographic structure of the ingot; (b) SEM picture of the ingot; (c) SEM structure of the homogenized alloy at 800 ℃/24 h; (d) metallographic structure of the solution-treated alloy at 820 ℃/2 h
圖 2 時效溫度對合金顯微硬度(a)和導電率(b)的影響
Figure 2. Variation in the microhardness (a) and conductivity (b) of the sample treated with different aging processes
圖 3 TEM組織明場像. (a)冷軋態; (b)350 ℃/2 h時效; (c)400 ℃/0.5 h時效; (d)400 ℃/2 h時效; (e)450 ℃/1 h時效; (f)450 ℃/8 h時效
Figure 3. TEM bright field images of the as-solution sample treated with (a) the cold rolling of 50% and aging at (b) 350 °C/2 h; (c) 400 °C/0.5 h; (d) 400 °C/2 h; (e) 450 °C/1 h; (f) 450 °C/8 h
圖 4 450 ℃/8 h一次時效后進行50%冷軋及二次時效TEM明場像形貌. (a)冷軋態; (b)400 ℃/1 h; (c) 400 ℃/2 h
Figure 4. TEM bright field images of the alloy after preaging at 450 °C/8 h, then cold rolling of 50%, followed by aging at (a) cold rolling; (b) 400 °C/1 h; (c) 400 °C/2 h
表 1 圖1(b)鑄態組織中區域A和B的元素分析(質量分數)
Table 1. EDS contents of the locations A and B in Fig.1(b)
% Location Ti Mg B La Cu Location A 1.47 0.10 0.03 0.06 98.34 Location B 45.92 0.11 0.06 0.04 53.87 
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表 2 合金二次時效處理過程中合金的硬度和導電率
Table 2. Microhardness and conductivity of the sample treated with different aging processes
Aging process Microhardness (HV) Conductivity/%IACS First aging 450 °C/8 h 310 18.9 First aging 450 °C/8 h + Cold rolling 50% 325 17.0 Secondary aging 400 °C/0.5 h 334 19.1 Secondary aging 400 °C/1 h 341 20.5 Secondary aging 400 °C/2 h 322 20.8
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參考文獻
[1] Gorsse S, Ouvrard B, Gouné M, et al. Microstructural design of new high conductivity-high strength Cu-based alloy. J Alloys Compd, 2015, 633: 42 doi: 10.1016/j.jallcom.2015.01.234 [2] Laughlin D E, Cahn J W. Spinodal decomposition in age hardening copper-titanium alloys. Acta Metall, 1975, 23(3): 329 doi: 10.1016/0001-6160(75)90125-X [3] Semboshi S, Amano S, Fu J, et al. Kinetics and equilibrium of age-induced precipitation in Cu-4 At Pct Ti binary alloy. Metall Mater Trans A, 2017, 48(3): 1501 doi: 10.1007/s11661-016-3949-x [4] Li S, Li Z, Xiao Z, et al. Microstructure and property of Cu?2.7Ti?0.15Mg?0.1Ce?0.1Zr alloy treated with a combined aging process. Mater Sci Eng A, 2016, 650: 345 [5] Li R P, Dong Y G, Wu M W, et al. Study on precipitation kinetics of phase transformation of cold rolled Cu?3Ti alloy foil. Hot Work Technol, 2020, 49(6): 136 doi: 10.14158/j.cnki.1001-3814.20182941李榮平, 董亞光, 武明偉, 等. 冷軋態Cu?3Ti合金箔時效析出相變動力學研究. 熱加工工藝, 2020, 49(6):136 doi: 10.14158/j.cnki.1001-3814.20182941 [6] Semboshi S, Kaneno Y, Takasugi T, et al. Effect of composition on the strength and electrical conductivity of Cu?Ti binary alloy wires fabricated by aging and intense drawing. Metall Mater Trans A, 2019, 50(3): 1389 doi: 10.1007/s11661-018-5088-z [7] Markandeya R, Nagarjuna S, Sarma D S. Precipitation hardening of Cu?Ti?Cr alloys. Mater Sci Eng A, 2004, 371(1-2): 291 doi: 10.1016/j.msea.2003.12.002 [8] Koike K, Clarke K D, Clarke A J. Microstructural evolution and mechanical properties of heavily cold-rolled and subsequently annealed Cu?3wt.%Ti alloys with nano-lamellar structure. JOM, 2019, 71(12): 4789 [9] Suzuki S, Hirabayashi K, Shibata H, et al. Electrical and thermal conductivities in quenched and aged high-purity Cu?Ti alloys. Scr Mater, 2003, 48(4): 431 doi: 10.1016/S1359-6462(02)00441-4 [10] Cao X M, Zhu Y B, Guo F A, et al. Hot deformation behavior and microstructure of Cu−Ti alloy. Rare Met Mater Eng, 2009, 38(Suppl 1): 509曹興民, 朱玉斌, 郭富安, 等. Cu−Ti合金的熱變形行為及其組織研究. 稀有金屬材料與工程, 2009, 38(增刊1): 509 [11] Liu J, Wang X H, Ran Q N, et al. Pre-deformation and aging characteristics of Cu?3Ti?2Mg alloy. Rare Met Mater Eng, 2018, 47(7): 1980 doi: 10.1016/S1875-5372(18)30168-1 [12] Semboshi S, Kaneno Y, Takasugi T, et al. High strength and high electrical conductivity Cu?Ti alloy wires fabricated by aging and severe drawing. Metall Mater Trans A, 2018, 49(10): 4956 doi: 10.1007/s11661-018-4816-8 [13] Ramesh S, Nayaka H S, Sahu S, et al. Influence of multiaxial cryoforging on microstructural, mechanical, and corrosion properties of copper-titanium alloy. J Mater Eng Perform, 2019, 28(12): 7629 doi: 10.1007/s11665-019-04454-9 [14] Szkliniarz A. Formation of microstructure and properties of Cu?3Ti alloy in thermal and thermomechanical processes. Arch Metall Mater, 2017, 62(1): 223 doi: 10.1515/amm-2017-0033 [15] Wei H, Wei Y H, Hou L F. The phase transition and applications of age hardening copper-titanium alloys. J Funct Mater, 2015, 46(10): 10001衛歡, 衛英慧, 侯利鋒. 時效硬化銅鈦合金的相變和應用. 功能材料, 2015, 46(10):10001 -
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