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Effect of aging treatment parameters on microstructure and properties of Cu-Ni-Si alloy

In this paper, effect of cold pre-deformation and sequent aging time and temperature on microstructure and properties of Cu-2.8Ni-1.0Si alloy are reported. The results shown that, hardness and electrical conductivity of alloy increase with increasing cold deformation degree after quenching and subsequent aging. | Journal of Science and Technology 54 (5A) (2016) 75-81 EFFECT OF AGING TREATMENT PARAMETERS ON MICROSTRUCTURE AND PROPERTIES OF Cu-Ni-Si ALLOY Phung Tuan Anh*, Le Minh Duc, Pham Dai Phuoc Military Technical Academy - Ministry of Defence, 236 Hoang Quoc Viet, Bac Tu Liem, Hanoi * Email: phungtuananhmta@gmail.com Received: 15 July 2016; Accepted for publication: 04 December 2016 ABSTRACT In this paper, effect of cold pre-deformation and sequent aging time and temperature on microstructure and properties of Cu-2.8Ni-1.0Si alloy are reported. The results shown that, hardness and electrical conductivity of alloy increase with increasing cold deformation degree after quenching and subsequent aging. With undeformed specimens after quenching, hardness and electrical conductivity of alloy reach maximum values with subsequent aging at 425 and 475 o C, respectively. Alloy attains maximum hardness of 255 HV5 with aging at 425 oC for 4.5 hours, while maximum electrical conductivity of 38.5 %IACS with aging at 475 oC for 8 hours. In the case of deformed specimens after quenching and subsequent aging, this rule is still preserved. Especially, at 70 % cold pre-deformation degree, alloy attains the maximum hardness of 274.3 HV5 with aging at 425 oC for 3.5 h, while maximum electrical conductivity reaches 42.4 % IACS with aging at 475 oC for 6 h. Keywords: Cu-2.8Ni-1.0Si alloy, cold pre-deformation, deformation degree, aging, Vickers hardness, electrical conductivity. 1. INTRODUCTION In all of the copper alloys used in electrical engineering, Cu-Ni-Si alloy have been considerable interest in the applications of leadframe, electrical contacts, bus conductor, electrodes. due to its high strength and good electrical conductivity [1 - 4]. Recently, the studies of Cu-Ni-Si alloy still continue to develop in many different priorities. Most studies about this alloy system aim to improve the mechanical properties, especially combination of high strength and good electrical conductivity