IN-SITU OBSERVATION OF SOLIDIFICATION OF Sn-Ag ALLOYS
Many alloy systems, that are candidates for lead-free solder, are classified into non-facet-facet eutectic alloy systems. Sn-Ag alloy is such an alloy and exhibits a complex solidified structure. Using a laser confocal microscope, in-situ observation of solidification process of Sn-Ag alloys have been made in this study. Hypo-eutectic, eutectic and hyper-eutectic alloys were prepared and the specimen was melted and solidified in the hot stage of laser microscope. The crucible was made of AI2O3 and its inner diameter was 4mm. In case of hypo-eutectic composition (Sn-2.0 mass％ Ag), primary Sn dendrite and eutectic were observed. In case of hyper-eutectic composition (Sn- 7.5 mass％ Ag), primary Ag3Sn and eutectic were observed in the range of cooling conditions in this study. On the other hand, in case of eutectic composition (Sn-3.5 mass％ Ag), the primary Sn dendrite and eutectic were observed. These observations qualitatively agree with the concept of coupled zone theory and experimental results which have been carried out by unidirectional solidification technique. The coupled zone of this alloy may be skewed towards to Ag rich side. The reason of this is that the undercooling which are necessary for growth are different for non-facet phase (=Sn) and facet phase (=Ag3Sn).
In-situ observation Dendrite Eutectic
Hisao Esaka Mizuho Sakuta Kei Shinozuka Manabu Tamura
Dept. of Materials Science and Engineering, National Defense Academy 1-10-20 Hashirimizu: Yokosuka 239-8686 Japan
国际会议
大连
英文
601-606
2007-08-19（万方平台首次上网日期，不代表论文的发表时间）