凝固速率对Sn-3.5Ag合金的凝固组织的影响

Influence of Solidification Rate on Microstructure Structure of Sn-3.5Ag Alloy

采用石墨模、钢模、水冷铜模和快速凝固甩带等方式，以金相显微镜、扫描电镜、X射线衍射等分析检测手段，系统研究了Sn-3.5Ag共晶合金在不同凝固速率的条件下，合金显微组织、相组成结构等的特征，分析了Sn-3.5Ag共晶合金在不同凝固速率下显微组织及相结构的变化规律。结果表明，Sn-3.5Ag共晶合金由β-Sn相和Ag3Sn相组成。石墨模冷却为规则的层片状共晶组织，钢模和水冷铜模冷却时，合金组织为细小的块状组织，快速甩带冷却为更加细小的块状组织。

Used the graphite die, steel mould, water-cooled copper mold and rapid solidification method, etc., and metallographic microscopy, scanning electron microscopy （SEM）, X-ray diffraction analysis and detection methods to systematically study the characteristics of the microstructure, phase composition of Sn-3.5Ag eutectic alloy under the conditions of different solidification rate. The results show that Sn-3.5Ag eutectic alloy is composed byβ-Sn phase and Ag3Sn phase. The microstructure is the regular arrangement of lamellar-type structures for graphite die cooling; The microstructure is the small block structure for metal mould and water-cooled copper mold cooling; when the solidification rate reached rejection with rapid solidification, the microstructure is finer block structure.