Sn-9Zn合金，無鉛銲錫的一種，共晶熔點472。K，UTS達103MPa且濕潤性
只略低於60Sn-40Pb，但耐氧化腐蝕性差，本研究擬添加Al來增加其耐蝕
性，但文獻中有關Sn-Zn-Al共晶合金熔點470。K，其顯微組織與拉伸機械
性質的研究甚少，因此本研究以Sn-X( 95Zn-5Al )〔X=5、10、15、20〕
為實驗材料來討論：1.化學組成、凝固速度與凝固組織三者之間的相布關
係。2.凝固組織與變形阻抗之間的探討。3.Sn-X( 95Zn-5Al )合金材料的
機械性質及其對溫度的依存性。實驗結果顯示，經熱差分析( DTA )，Sn-
X( 95Zn-5Al )合金熔點約為472。K。再從金相組織觀察得知，這四種合
金材料之凝固組織涵蓋了亞共晶成分與過共晶成分，其凝固組織因95Zn-5
Al含量的增加，由樹枝狀晶組織逐漸變化為具有針狀或羽狀初晶Zn之過共
晶組織，且上述組織因凝固速度增快有明顯細化的傾向。根據拉伸試驗分
析，Sn-X( 95Zn-5Al )合金UTS達98MPa，其抗拉強度會因95Zn-5Al添加量
的增加，會有上升的傾向，但延性會降低。若溫度升高，強度會下降，延
性則增加；溫度降低，則強度升高，延性呈單純下降傾向。銲點之凝固組
織受質量效應的影響，凝固速度愈快，各試材之凝固組織明顯有細化的傾
向，但根據硬度試驗結果，各試材之平均微硬度值不因凝固組織改變而有
明顯的差異。其流應力較含鉛銲錫高，總延伸率較含鉛銲錫低，但常溫中
仍維持有15%以上的延伸率；硬變應化指數約為0.43，顯示具有良好的塑
性變形能力。

Sn-9Zn alloy , one of the Lead-Free solders , has 472。K
eutectic Melting point and 103MPa ultimate tensile strength .
Its wetability is a little inferior to 60Sn-40Pb alloy's and it
is susceptible to oxidation and corrosion . In this research ,
Al was introduced into Sn-9Zn alloy to improve its corrosion
resistance . Because of little reference about microstructure
and mechanical properties of Sn-Zn-Al alloy , this reach made
experiments with Sn-X( 95Zn-5Al )〔X=5、10、15、20〕alloy there
are three topices in this research , including (1) the
relationship amony chemical component , solidification rate and
solidification structure (2) the interaction between
solidification structure and deformation resistance (3) the
mechanical properties and temperature effect of Sn-X( 95Zn-5Al )
alloys .According to differential thermal analysis (DTA) , the
melting point of Sn-X( 95Zn-5Al ) alloys reach 472。K , and from
the morphology of their microstructure, there exist hypoeutectic
structure and hypereutectic structure in the solidification
structure . The higher content of 95Zn-5Al , the more dentrite
that turn to accicularor feather proeutectic Zn . Increase
solidification rate , the structure tend to finer .From the
result of tensile test show that , Sn-X( 95Zn-5Al ) alloy's UTS
reach upon 98MPa , when increase 95Zn-5Al content , their
tensile strength will increase , but elongation decrease . The
highter temperature , the highter elongation but lower , and the
lower temperature , the highter strength but lower elongation .
The solidification structure of weldpoint is afected with mass
effect . Increasing solidification rate , the structure turn to
finely . Accroding one results of hardness test , there are no
observing difference in hardness for different Structure . Its
flow stress higher than Sn-Pb Solders , total elongation lower
than Sn-Pb Solders , but in room temperature still has 15%
elongation ; strain-hardening exponent is 0.43 , it show that
Sn-X( 95Zn-5Al ) alloy has good plastic deformation .
Sn-9Zn alloy , one of the Lead-Free solders , has 472。K