摘要
以Ag-28Cu和Ag-9Pd-9Ga两种银基钎料钎焊C/SiC复合材料和Al_2O_3陶瓷与Ti55钛合金接头,考察了钎料和钎焊工艺对接头焊缝组织形貌变化影响.结果表明,采用Ag-28Cu钎料在850~920℃温度区间钎焊C/SiCTi55和Al_2O_3-Ti55接头均在陶瓷基体近钎焊界面区域开裂,原因为Ti55合金中Ti元素大量溶解扩散并与铜反应生成的大量脆性Cu-Ti化合物恶化焊缝塑性.Ag-9Pd-9Ga钎料则可以获得完整接头,钎焊过程中Pd,Ga元素在Ti55侧钎焊界面富集并与Ti元素反应生成PdTi,Ti2Ga,Ti4Pd化合物的反应层,有效抑制了元素往焊缝中的溶解扩散.
C/SiC composite and Al_2O_3 ceramic are brazed to Ti55 titanium alloy by active brazing method using Ag-28 Cu and Ag-9 Pd-9 Ga filler metals,respectively. The effect of filler metal and brazing process on the microstructure of joints are investigated. The results show that for the joints of C/SiC-Ti55 and Al_2O_3-Ti55 using active Ag Cu brazing material at brazing temperature between 850 ~ 920 ℃,obvious cracks are found in composites and/or ceramic matrix near the composite/braze interface. The microstructure of joints is mainly composed of brittle Cu-Ti compounds formed as a result of extensive interdiffusion and reaction of active Ti with Cu element from brazing material.On the other hand,C/Si C-Ti55 and Al_2O_3-Ti55 joints brazed with Ag-9 Pd-9 Ga filler metal are perfectly bonded. A continuous reaction layer with high concentrations of Ti,Pd and Ga is detected at the braze/Ti55 interface. The EDS and XRD examination show that this reaction layer is comprised of Pd Ti,Ti2 Ga and Ti4 Pd compounds. The segregation of Pd,Ga at braze/Ti55 interface is due to the strong chemical affinity between Pd,Ga and Ti. As a result,the diffusion and chemical reactions of the solute Ti in molten braze during brazing are suppressed.
出处
《焊接学报》
EI
CAS
CSCD
北大核心
2017年第9期75-78,共4页
Transactions of The China Welding Institution
基金
"国家国际科技合作计划项目"(2015DFA50470)
高档数控机床与基础制造装备科技重大专项课题(2014ZX04001131)
