Abstract
Aging treatment of Cu-based alloys is essential to enhance their strength that is desirable for their exten-sive engineering applications in electrical industry,whereas the underlying mechanism of strengthening is essential for massive manufacturing of these alloys.Here,the microstructure evolution of a supersatu-rated solid solution Cu-15Ni-8Sn-0.2Nb alloy aged at 400℃for different time was characterized at atomic scale using state-of-the-art transmission electron microscopy(TEM)and the corresponding mechanical property was also measured.The results reveal that the modulated structure,DO22/L12 ordering,and discontinuous precipitation(DP)appeared in the advances of aging time.At the early stage of aging treatment,component modulation waves and satellite spots appeared from spinodal decomposition and the modulation wavelength was identified in the range of 1-7 nm.Subsequently the modulated struc-tures formed-poor-rich solute regions,of which DO22 ordering was present in the Ni-poor region while L1 2 ordering appeared in the Ni-rich region.The sequence of ordering precipitates was further verified by density functional theory(DFT)simulations.Furthermore,orientation relationships and interfacial structures between DO22,L12 phases and the parent matrix were determined.The measured hardness of alloy reached a maximum value of 335 HV after aging for 120 min due to the coherence between the two ordering phases and matrix.These results illustrated the importance of aging on structural evolution and mechanical property of Cu-15Ni-8Sn alloy at various heat treatment stages,which could potentially help in manufacturing promising alloys for their extensive engineering applications.
基金项目
This work was supported by the National Natural Science Foun-dation of China[grant(numbers 51971135)
This work was supported by the National Natural Science Foun-dation of China[grant(518210011)
NETL
NSTL
维普
万方数据