真空熔铸法和快速凝固法制备的Cu-15Ni-8Sn-Xsi合金的组织研究

利用金相、扫描电镜及电子能谱微区成分分析等方法对采用真空熔铸法和快速凝固法制备的不含Si及添加不同Si含量(0．3％和1．2％)的Cu-15Ni-8Sn合金的铸态组织形貌及构成进行了研究。结果发现，采用真空熔铸法所制备的合金的铸态组织具有发达的枝晶，且明显地分为3层，添加的Si由于与Ni结合生成Ni3Si相而细化了枝晶。与真空熔铸法相比，采用快速凝固法制备的添加少量Si的合金，其晶粒均匀细小，枝晶基本消除，微区成分更均匀。相对Si含量较少(0．3％)的合金，当Si含量增加到1．2％时，由于Si抑制了Sn在基体中的固溶度，导致合金中Sn的显微偏析有所加剧。

A Study on Cast Structure of Cu-15Ni-8Sn-Xsi Alloys Prepared by Vacuum Melting and Rapid Solidification

The cast structures and component of vacuum melten and rapid solidified Cu-15Ni-8Sn alloys without Si or with different addition levels of Si (0.3% and 1.2%) were studied by optical microscope, SEM and energy spectrum analysis. It was found that the alloys prepared by vacuum melting had coarse treelike crystals, which apparently were in three layers. The addition of Si refined the treelike crystals due to the formation of Ni_3Si phase. As for the alloys prepared by rapid solidification, the results indicated that their grains were uniform and fine, the treelike crystals were almost eliminated, and the micro composition was more homogeneous. As compared to the alloy with a small amount of Si (0.3%), the micro-segregation of Sn in the alloy with 1.2%Si grew in intensity because the solubility of Sn was suppressed by the addition of Si.