Evolution of precipitated phases in high strength and high electrical conductivity Cu-Cr-Zr alloy during aging

doi:10.13251/j.issn.0254-6051.2021.07.002

Abstract

Abstract: Precipitated phases in a CuCrZr alloy after aging at different temperatures were observed, and the electrical conductivity of the alloy was tested. The results show that after aging at 450 ℃ for 30 min, pure Cr precipitates with diameter of less than 5 nm are produced and obey the cube-on-cube orientation relationship with the matrix. After peek aging at 450 ℃ for 120 min, the precipitates are indexed as CrCu₂Zr and Cr, which are coherent with the matrix and in a size of about 10 nm. After over aging at 600 ℃ and 800 ℃ respectively for 30 min, the precipitates change into rod-like Cu₄Zr and spherical Cr phases. When aging at 600 ℃, some of the rod-like precipitates have grown to about 50 μm. When aging at 800 ℃, almost no fine precipitates are found, while the rod-shaped Cu₄Zr precipitates grow to more than 200 μm, and the spherical pure Cr precipitates to near 50 μm. The electrical conductivity of the CuCrZr alloy increases with the extension of the aging time during aging at 450 ℃ and reaches the maximum value at 120 min and then hardly changes. Based on the linear relationship between the conversion rate of precipitated phases and the electrical conductivity during aging process, the precipitation kinetics equations of the CuCrZr alloy aging at 400, 450, 500 and 600 ℃ are established.

Key words: CuCrZr alloy, precipitates, evolution of microstructure, electrical conductivity, kinetics equation

CLC Number:

TG142.1

Pan Xuexin, Jiang Haichang, Feng Hui, Li Xuebin, Lu Yanren, Hu Xiaofeng, Fu Hong. Evolution of precipitated phases in high strength and high electrical conductivity Cu-Cr-Zr alloy during aging[J]. Heat Treatment of Metals, 2021, 46(7): 7-12.

References

[1] Batawi E, Morris D G, Morris M A. Effect of small alloying additions on behaviour of rapidly solidified Cu-Cr alloys[J]. Materials Science and Technology, 1990, 6(9): 892-899.
[2] Vinogradov A, Ishida T, Kitagawa K, et al. Effect of strain path on structure and mechanical behavior of ultra-fine grain Cu-Cr alloy produced by equal-channel angular pressing[J]. Acta Materialia, 2005, 53(8): 2181-2192.
[3] Correia J B, Davies H A, Sellars C M. Strengthening in rapidly solidified age hardened Cu-Cr and Cu-Cr-Zr alloys[J]. Acta Materialia, 1997, 45(1): 177-190.
[4] Su J H, Dong Q M, Liu P, et al. Research on aging precipitation in a Cu-Cr-Zr-Mg alloy[J]. Materials Science and Engineering A, 2005, 392(1/2): 422-426.
[5] Batawi E, Biselli C, Gunther S, et al. Thermomechanical processing of spray-formed Cu-Cr-Zr alloy[J]. Scripta Metallurgica et Materialia, 1993, 29(6): 765-769.
[6] Holzwarth U, Stamm H. The precipitation behaviour of ITER-grade Cu-Cr-Zr alloy after simulating the thermal cycle of hot isostatic pressing[J]. Journal of Nuclear Materials, 2000, 279(1): 31-45.
[7] 刘国辉, 赵四祥, 彭凌剑, 等. CuCrZr合金中沉淀相的控制[J]. 金属热处理, 2015, 40(4): 1-6.
Liu Guohui, Zhao Sixiang, Peng Lingjian, et al. Control of precipitates in CuCrZr alloy[J]. Heat Treatment of Metals, 2015, 40(4): 1-6.
[8] 石凤健, 王雷刚, 王海龙, 等. 等径角挤压工艺对固溶状态CuCrZr合金性能的影响[J]. 金属热处理, 2007, 32(1):81-83.
Shi Fengjian, Wang Leigang, Wang Hailong, et al. Effect of equal-channel angular pressing on properties of CuCrZr alloy as solid solution[J]. Heat Treatment of Metals, 2007, 32(1):81-83.
[9] Batra I S, Dey G K, Kulkarni U D, et al. Precipitation in a Cu-Cr-Zr alloy[J]. Materials Science and Engineering A, 2003, 356(1/2): 32-36.
[10] Huang F, Ma J, Ning H, et al. Analysis of phases in a Cu-Cr-Zr alloy[J]. Scripta Materialia, 2003, 48(1): 97-102.
[11] Huang F X, Yang H, Tang L W, et al. Analysis of as-cast microstructure in a Cu-Cr-Zr-Fe-Ti alloy[C]//Proceedings of the 7th National Conference on Chinese Functional Materials and Applications, 2010: 806-810.
[12] Tang N Y, Taplin D, Dunlop G L. Precipitation and aging in high-conductivity Cu-Cr alloys with additions of zirconium and magnesium[J]. Metal Science Journal, 2013, 1(4): 270-275.
[13] Mu S G, Guo F A, Tang Y Q, et al. Study on microstructure and properties of aged Cu-Cr-Zr-Mg-RE alloy[J]. Materials Science and Engineering A, 2008, 475(1/2): 235-240.
[14] 刘平, 康布熙, 曹兴国, 等. 快速凝固Cu-Cr合金时效析出的共格强化效应[J]. 金属学报, 1999, 35(6): 561-564.
Liu Ping, Kang Buxi, Cao Xingguo, et al. Coherent strengthening of aging precipitation in rapidly solidified Cu-Cr alloy[J]. Acta Metallrugica Sinica, 1999, 35(6): 561-564.
[15] Lei Jingguo, Liu Ping, Tian Baohong, et al. Loss in coherency and coarsening behavior of Cr precipitates in Cu-Ag-Cr[J]. Transactions of Nonferrous Metals Society of China, 2005(S3): 185-188.
[16] 雷静果. 新型高强高导Cu-Ag-Cr合金的组织性能及时效动力学研究[D]. 西安: 西安理工大学, 2007.
Lei Jingguo.Research on microstructures and properties and aging kinetics of new high strength and high conductivity Cu-Ag-Cr alloy[D]. Xi'an: Xi'an University of Technology, 2007.
[17] Su J, Ping L, Li H, et al. Phase transformation in Cu-Cr-Zr-Mg alloy[J]. Materials Letters, 2007, 61(27): 4963-4966.
[18] Badji R, Bouabdallah M, Bacroix B, et al. Effect of solution treatment temperature on the precipitation kinetic of σ-phase in 2205 duplex stainless steel welds[J]. Materials Science and Engineering A, 2008, 496(1/2): 447-454.
[19] 陈健, 刘雪飘, 梁欢. 铜镍钴铍合金的时效相变动力学方程[J]. 机械工程材料, 2011, 35(1): 19-21.
Chen Jian, Liu Xuepiao, Liang Huan. Aging transformation kinetic equation of CuNiCoBe alloy[J]. Materials for Mechanical Engineering, 2011, 35(1): 19-21.