Microstructural characterization of Cu/Al composites and effect of cooling rate at the Cu/Al interfacial region

Abstract

Cu/Al composites are of vital importance in industrial applications because of their numerous advantages. The influence of bonding temperature and cooling rate on the microstructure and morphology of Cu/Al composites was investigated in this paper. The interfacial morphology and constituent phases at the Cu/Al interface were analyzed by optical microscopy and field-emission scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy. The results indicate that effective Cu-Al bonding requires a higher bonding temperature to facilitate interdiffusion between the two metals. The microstructural characteristics are associated with various bonding temperatures, which impact the driving force of interdiffusion. It is observed that cooling rate exerts a significant influence on the morphology and amount of the intermetallic compounds at the interfacial region. Meanwhile, microhardness measurements show that hardness varies with the bonding temperature and rate of cooling.

Keywords

composite materials / copper / aluminum / temperature / cooling rate / interfaces / diffusion bonding

References

[1] Hsieh CC, Shi MS, Wu WT. Growth of intermetallic phases in Al/Cu composites at various annealing temperatures during the ARB process. Met. Mater. Int., 2012, 18(1): 1.

[2] Guo YJ, Qiao GJ, Jian WZ, Zhi XH. Microstructure and tensile behavior of Cu-Al multi-layered composites prepared by plasma activated sintering. Mater. Sci. Eng. A, 2010, 527(20): 5234.

[3] Lee KS, Kwon YN. Solid-state bonding between Al and Cu by vacuum hot pressing. Trans. Nonferrous Met. Soc. China, 2013, 23(2): 341.

[4] Eslami P, Taheri AK. An investigation on diffusion bonding of aluminum to copper using equal channel angular extrusion process. Mater. Lett., 2011, 65(12): 1862.

[5] Xue P, Xiao BL, Ni DR, Ma ZY. Enhanced mechanical properties of friction stir welded dissimilar Al-Cu joint by intermetallic compounds. Mater. Sci. Eng. A, 2010, 527(21–22): 5723.

[6] Tan CW, Jiang ZG, Li LQ, Chen YB, Chen XY. Microstructural evolution and mechanical properties of dissimilar Al-Cu joints produced by friction stir welding. Mater. Des., 2013, 51, 466.

[7] Zare GR, Divandari M, Arabi H. Investigation on interface of Al/Cu couples in compound casting. Mater. Sci. Technol., 2013, 29(2): 190.

[8] Su YJ, Liu XH, Huang HY, Liu XF, Xie JX. Interfacial microstructure and bonding strength of copper cladding aluminum rods fabricated by horizontal core-filling continuous casting. Metall. Mater. Trans. A, 2011, 42(13): 4088.

[9] Lee TH, Lee YJ, Park KT, Nersisyan HH, Jeong HG, Lee JH. Controlling Al/Cu composite diffusion layer during hydrostatic extrusion by using colloidal Ag. J. Mater. Process. Technol., 2013, 213(3): 487.

[10] Sayyedain SS, Salimijazi HR, Toroghinejad MR, Karimzadeh F. Microstructure and mechanical properties of transient liquid phase bonding of Al₂O₃ P/Al nanocomposite using copper interlayer. Mater. Des., 2014, 53, 275.

[11] Hug E, Bellido N. Brittleness study of intermetallic (Cu, Al) layers in copper-clad aluminium thin wires. Mater. Sci. Eng. A, 2011, 528(22–23): 7103.

[12] Xu B, Tong WP, Liu CZ, Zhang H, Zuo L, He JC. Effect of high magnetic field on growth behavior of compound layers during reactive diffusion between solid Cu and liquid Al. J. Mater. Sci. Technol., 2011, 27(9): 856.

[13] Elrefaey A, Tillmann W. Solid state diffusion bonding of titanium to steel using a copper base alloy as interlayer. J. Mater. Process. Technol., 2009, 209(5): 2746.

[14] Divandari M, Vahid AR. Golpayegani, Study of Al/Cu rich phases formed in A356 alloy by inserting Cu wire in pattern in LFC process. Mater. Des., 2009, 30(8): 3279.

[15] Liu N, Jie JC, Lu YP, Wu L, Fu Y, Li TJ. Characteristics of clad aluminum hollow billet prepared by horizontal continuous casting. J. Mater. Process. Technol., 2014, 214(1): 60.

[16] Natsume Y, Ohsasa K, Tayu Y, Momono T, Narita T. Numerical modeling of the transient liquid-phase diffusion bonding process of Al using Cu filler metal. ISIJ Int., 2003, 43(12): 1976.

[17] Nami H, Halvaee A, Adgi H, Hadian A. Investigation on microstructure and mechanical properties of diffusion bonded Al/Mg2Si metal matrix composite using copper interlayer. J. Mater. Process. Technol., 2010, 210(10): 1282.

[18] He P, Feng JC, Zhang BG, Qian YY. Microstructure and strength of diffusion-bonded joints of TiAl base alloy to steel. Mater. Charact., 2002, 48(5): 401.

[19] Calvo FA, Ureng A, Gomez De Salazar JM, Molleda F. Special features of the formation of the diffusion bonded joints between copper and aluminium. J. Mater. Sci., 1988, 23(6): 2273.

[20] Liu XR, Cao CD, Wei B. Microstructure evolution and solidification kinetics of undercooled Co-Ge eutectic alloys. Scripta Mater., 2002, 46(1): 13.

[21] Jordan RM, Hunt JD. Morphological observations of the eutectic-dendrite breakdown in the Al-CuAl₂ system. J. Cryst. Growth, 1971, 11(2): 141.

[22] Aravind M, Yu P, Yau MY, Ng DHL. Formation of Al₂Cu and AlCu intermetallics in Al(Cu) alloy matrix composites by reaction sintering. Mater. Sci. Eng. A, 2004, 380(1–2): 384.

[23] Gu XY, Sun DQ, Liu L, Duan ZZ. Microstructure and mechanical properties of transient liquid phase bonded TiC_P/AZ91D joints using copper interlayer. J. Alloys Compd., 2009, 476(1–2): 492.

[24] Pouranvari M, Ekrami A, Kokabi AH. Effect of bonding temperature on microstructure development during TLP bonding of a nickel base superalloy. J. Alloys Compd., 2009, 469(1–2): 270.

[25] Devaraj S, Sankaran S, Kumar R. Influence of spark plasma sintering temperature on the densification, microstructure and mechanical properties of Al-4.5 wt.%Cu alloy. Acta Metall. Sin. Engl. Lett., 2013, 26(6): 761.

[26] Bai Q, Hao YF, Wang J, Man H, Tang YJ, Xu H, Xia S. Effect of cooling rate on the magnetic properties of Fe₅₃Nd₃₇Al₁₀ alloy. Int. J. Miner. Metall. Mater., 2013, 20(5): 440.

[27] Kawakami H, Suzuki J, Nakajima J. Bonding process of Al/Cu dissimilar bonding with liquefaction in air. Weld. Int., 2007, 21(12): 836.

[28] Lee KS, Lee YS, Kwon YN. Influence of secondary warm rolling on the interface microstructure and mechanical properties of a roll-bonded three-ply Al/Mg/Al sheet. Mater. Sci. Eng. A, 2014, 606, 205.