高性能Cu-Ni-Co-Si合金的二次时效行为及析出相特征

Re-aging behaviour and precipitated phase characteristics of high-performance Cu-Ni-Co-Si alloy

采用显微硬度计、电导仪、透射电镜(TEM)和能谱仪(EDS)等研究了二次时效Cu-1.6Ni-1.2Co-0.6Si合金的性能和显微结构;根据衍射花样标定和能谱结果,分析了合金的析出相特征。结果表明:合金冷轧过程中形成的高密度位错,促进了二次时效析出相的析出;这些二次析出相与一次时效析出相具有相同的结构和组成,都是正交结构的(Ni,Co)2Si;但二次时效析出相分布更密集、尺寸更细小;二次时效后合金硬度的提高主要是由这些细小密集的δ-(Ni, Co)2Si相的强化所贡献;析出相与铜基体之间的位向关系为:(001)Cu//(001)p,[110]Cu//[010]p。

Properties and microstructure of re-aging Cu-1.6 Ni-1.2 Co-0.6 Si alloy were investigated by means of microhardness tester,conductometer,transmission electron microscopy(TEM)and energy dispersive spectrometer(EDS)analysis.According to the results of diffraction pattern calibration and energy spectrum,the precipitated phase characteristics of the alloy were analyzed.The results show that the high density dislocation formed during cold-rolling promote the precipitation of re-aged precipitates,and these re-aged precipitates have the same structure and composition as first-aged precipitates,all of which are identified to be the orthorhombic(Ni,Co)2Si.However,the distribution of the re-aged precipitates is more dense and the size is smaller than that of the first-aged precipitates,and the increase in the hardness of the alloy after re-aging is mainly due to the strengthening of these fine and denseδ-(Ni,Co)2Si precipitated phases.The crystal orientation relationship between copper matrix and precipitated phase is as follows:(001)Cu//(001)p and[110]Cu//[010]p.