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1 ZHSi80-3合金组织分析ZHSi80-3是硅黄铜,成分是:79%～81%Cu,2.5%～4.5%Si,其余为Zn.图1是ZHSi80-3的两种组织.图1a中可观察到两种白亮物:一种是树枝状白亮物;另一种是带尖角的不规则块状或条状白亮物,这种白亮物数量较少.还可观察到分布于两种白亮物之间的黑色物.如果再仔细观察,可发现黑色物与树枝状白亮物之间的明暗度是逐渐变化的,而且没有明确的界线(如果放大倍数更高一些,这一特征更明显).而黑色物与带尖角的块状或条状白色物之间明暗度是突变的,界线明确.根据上述特征,可以认为树枝状白色物与黑色物是同一个相或者说是同一种组成物,之所以明暗度不同是枝晶偏析所致.带尖角的白色块状及条状物则是另一种组成物.综上所述,由观察可初步判断图1a的组织组成物有两种:一种是存在枝晶偏折的树枝晶;另一种是分布于树枝晶之间的白亮块状或条状物.而且由这两种组成物的分布可知其形成顺序是前一种组成物最先凝固形成,后一种组成物最后凝固形成.图1b的组织特征与图1a相近,其区别在于白色块状、条状物数量极少.仔细观察才可发现树枝晶之间存在极少的白亮细粒状组成物.现在需要分析确定图1中的两种组成物分别是什么合金相或组织.ZHSi80-3合金是在普通黄铜的基础上加入一定量的Si而成.加入Si对组织的影响?
1 ZHSi80-3 alloy microstructure analysis ZHSi80-3 is a silicon brass, the composition is: 79% ~ 81% Cu, 2.5% ~ 4.5% Si, the rest is Zn. Figure 1 is ZHSi80-3 two organizations. There are two types of white matter that can be observed: one is dendritic white and the other is an irregular block or strip of white light with sharp corners, which is less in number, and is observed in two If you look closely, you can see that the darkness between the black and the dendrites changes gradually and there is no clear boundary (this feature is more pronounced if the magnification is higher ) .But black and sharp with lumps or bar white matter between the brightness is a mutation, the line clear.According to the above characteristics, it can be considered dendritic white and black is the same phase or the same Composition, the reason why the difference is due to the dendrite segregation due to sharp white patches and stripes is another composition.In summary, from the observation can be initially judged in Figure 1a tissue composition There are two kinds: one is dendrites with dendrite deflection and the other is white lumps or strips distributed between dendrites. From the distribution of the two compositions, it can be seen that the formation order is that the first composition is the first to be solidified and the latter one is finally solidified. The tissue features of FIG. 1b are similar to those of FIG. 1a, except that the white lumps, A very small number of objects observed carefully before we can see the existence of very few white dendrite fine white granular composition now need to analyze the two components in Figure 1 were identified what the alloy phase or tissue.ZHSi80-3 alloy is On the basis of ordinary brass by adding a certain amount of Si made by adding Si on the organization?