The study of dynamic wetting behavior of active brazes containing various Ti on Al2O3 substrate using infrared rapidly heating
Date Issued
2004
Date
2004
Author(s)
Huang, Ying-Hsiang
DOI
zh-TW
Abstract
Dynamic wetting angle (DWA) and interface microstructure of Ag-Cu-Ti active brazing alloys on 95wt.% Al2O3 by infrared heating were investigated and analyzed in the study. Experimental results show that Ag-26.7Cu-4.5Ti (wt.%) has better wettability than Ag-27.5Cu-1.9Ti (wt.%) and the data between wetting angle and time is reproduced quite well which can be fitted by Ambrose equation with suitable corrected characteristic time.The microstructural observations show that the interface of Ag-26.7Cu-4.5Ti/Al2O3 forms Ti3.3Cu2.7O layer﹐and that of Ag-27.5Cu-1.9Ti/ Al2O3 forms Ti3Cu3O and TiOx layers. For the latter case﹐TiOx can also form on the melt filler’s surface and block the filler to absorb infrared heat which causes the wettability of Ag-27.5Cu-1.9Ti to be independent of brazing temperature.The DWA of Ti-15Cu-15Ni(wt.%) filler alloy on 95wt.% and 99.5wt.% Al2O3 substrates were also studied.The wettability and interface microstructure are affected mostly by the filler alloy due to its high active Ti content﹐but are not so much affected by the purity of Al2O3 substrate.Because of the Cu concentration in Ti-15Cu-15Ni alloy is not high enough, the melting point of Ti-15Cu-15Ni alloy does not decrease too much.This feature causes the wettability of Ti-15Cu-15Ni/Al2O3 is inferior to that of Ag-Cu-Ti/Al2O3. In this study﹐we also used Ag-5Al (wt.%) filler alloy to wet pure Ti and pure Cu substrates. In pure Ti substrate﹐the interface is TiAl phase at 850℃ and is Ag2TiAl phase at 900℃ with the latter having the superior wettability.In pure Cu substrate,Ag and Cu atoms can react severely to form hypereutectic structure to cause its melting point decrease and thus improve its wettability.
Subjects
Ag-Cu-Ti
動態潤濕性
界面顯微組織
活性硬銲填料
Ti-15Cu-15Ni
Ag-5Al
Active brazing alloys
Interface microstructure
D
Type
thesis
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