Precipitation Behavior of Cu-1.9Be-0.3Ni-0.15Co Alloy During Aging

doi:10.1007/s40195-014-0198-0

Abstract

Abstract:

In this paper, the evolutions of microstructure and mechanical properties of Cu-1.9Be-0.3Ni-0.15Co alloy were studied. The alloys in the condition of the solution treated (soft state) and 37% cold rolled (hard state) were aged at 320 °C for different time, respectively. The mechanical properties, electrical conductivity and microstructure of the alloy aged for different time were analyzed. Additionally, the precipitation kinetics of Cu-1.9Be-0.3Ni-0.15Co alloys was investigated. X-ray diffraction and transmission electron microscopy results reveal that both continuous precipitation and discontinuous precipitation existed in the hard-state Cu-1.9Be-0.3Ni-0.15Co alloy during the whole aging process; the sequence of continuous precipitation is G.P. zone → γ″ → γ′ → γ. Furthermore, the precipitation transformation mechanism of soft-state alloy is homogeneous nucleation, while hard-state alloy shows the heterogeneous nucleation (interface nucleation) with the nucleation rate of both states decaying rapidly to zero during aging at 320 °C.

Key words: Cu-1.9Be-0.3Ni-0.15Co alloy, Aging, Microstructure, Mechanical property, Electrical property, Precipitation kinetics

Yan-Chuan Tang, Yong-Lin Kang, Li-Juan Yue, Xiao-Liang Jiao. Precipitation Behavior of Cu-1.9Be-0.3Ni-0.15Co Alloy During Aging[J]. Acta Metallurgica Sinica (English Letters), 2015, 28(3): 307-315.

Figures/Tables 14

Fig. 1 XRD patterns of Cu-1.9Be-0.3Ni-0.15Co specimens aged for different time: a soft-state specimens; b hard-state specimens

Fig. 2 Fraction of precipitates in Cu-1.9Be-0.3Ni-0.15Co alloy aged for different time

Fig. 3 TEM image a and the selected area electron diffraction (SAED) pattern b of hard-state Cu-1.9Be-0.3Ni-0.15Co alloy aged at 320 °C for 10 min

Fig. 4 TEM image a and the selected area electron diffraction (SAED) pattern b of hard-state Cu-1.9Be-0.3Ni-0.15Co alloy aged at 320 °C for 30 min

Fig. 5 TEM image a and the selected area electron diffraction (SAED) pattern b of hard-state Cu-1.9Be-0.3Ni-0.15Co alloy aged at 320 °C for 120 min

Fig. 6 TEM image of hard-state Cu-1.9Be-0.3Ni-0.15Co alloy aged at 320 °C for 360 min

Fig. 7 Grain boundary precipitates during aging process: a SE-SEM of grain boundary precipitates; b morphology of grain boundary precipitates with magnification of ×10,000; c BE-SEM image of grain boundary precipitates

Fig. 8 Discontinuous precipitation of Cu-1.9Be-0.3Ni-0.15Co alloy aged for different time: a 15 min; b 120 min; c 360 min

Fig. 9 Tensile properties of Cu-1.9Be-0.3Ni-0.15Co alloy aged at 320 °C for different time: a hard state with thickness of 0.17 mm; b soft state with thickness of 0.27 mm

Fig. 10 Vickers hardness of Cu-1.9Be-0.3Ni-0.15Co alloy aged for different time

Fig. 11 Conductivity of Cu-1.9Be-0.3Ni-0.15Co alloy aged for different time

Fig. 12 Relationship between log(ln(1/(1-X))) and log(t) of the soft-state Cu-1.9Be-0.3Ni-0.15Co alloy

Fig. 13 Relationship between log(ln(1/(1-X))) and log(t) of the hard-state Cu-1.9Be-0.3Ni-0.15Co alloy

Fig. 14 Relationship between transformation ratio of precipitates and aging time

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