Co对Cu-Ni-Si合金时效早期析出相变的影响

Effect of Co on Precipitation Phase Transformation of Cu-Ni-Si Alloy during Early Aging

采用感应熔炼和热轧的加工方式制备了不同Co含量的Cu-Ni-Si系列合金,对合金进行了不同温度的固溶处理和500℃的时效处理,利用相图计算方法和透射电子显微镜检测手段研究了Co元素添加对Cu-Ni-Si合金时效早期析出相变的影响。结果表明:随着时效温度的升高,Cu-Ni-Si合金中的时效析出Fcc+Ni2Si两相区域会变宽;Cu-Ni-Co-Si合金中主要存在Ni2Si和Co2Si两种析出相,Ni2Si相所占的分数随着Ni/Co比的增加逐渐增大,Co2Si相所占的分数则与之相反;在时效早期,Co元素能够加速Cu-Ni-Si系列合金中原子的扩散,促进析出相的析出,同时Co元素在时效早期能够抑制Cu-Ni-Si系列合金发生调幅分解,从而直接析出(Ni,Co)2Si相。

The Cu-Ni-Si series alloys with different Co contents were prepared by induction smelting and hot rolling,the alloys were treated by solid solution at different temperatures and aged at 500 ℃,phase diagram calculations and transmission electron microscopy were used to investigate the effect of Co on the precipitation transformation of Cu-Ni-Si alloys during early ageing.The results show that with the increase of aging temperature,the precipitation of Fcc+Ni2Si two-phase region in the Cu-Ni-Si alloy will become wider;there are two kinds of precipitation phases,Ni2Si and Co2Si,in Cu-Ni-Co-Si alloys,the fraction of Ni2Si phase gradually increases with the increase of Ni/Co ratio,and the fraction of Co2Si phase occupies the opposite.During early ageing,Co element can accelerate the diffusion of atoms in Cu-Ni-Si alloys and promote the precipitation of precipitates,at the same time,Co element can inhibit the early aging spinodal decomposition of Cu-Ni-Si alloys and (Ni,Co)2Si phase can be precipitated directly.