Ti活度对Al_2O_3/Ag-Cu-Ti/Fe-Ni-Co钎焊接头力学性能和微观组织结构的影响（英文）

Effects of Ti Activity on Mechanical Properties and Microstructures of Al_2O_3/Ag-Cu-Ti/Fe-Ni-Co Brazed Joints

采用Ag Cu Ti钎料实现了Al_2O_3陶瓷与Fe-Co-Ni合金的钎焊连接,并调查了不同钛含量的钎料对Al_2O_3/Ag-Cu-Ti/Fe-Ni-Co钎焊接头机械性能和微观组织结构的影响。利用扫描电镜(SEM),X射线能量谱仪(EDS),X射线衍射仪(XRD)及电子万能试验机研究了钎焊接头的力学性能和微观组织结构。结果表明,钛含量的增加明显提高Ag-Cu-Ti钎料与Al_2O_3陶瓷的相互作用,在Al_2O_3/Ag-Cu-Ti界面生成一层由Ti-Al和Ti-O化合物组成的反应层。Al_2O_3/Ag-Cu-Ti/Fe-Ni-Co钎焊接头的抗拉强度随钛含量的增加而增加,当钛含量提高到8%(质量分数)时,抗拉强度达到最大值78 MPa。通过微观组织结构分析发现,采用AgCu4Ti在890℃保温5 min的条件下可以获得较好的钎焊接头,典型接头的微观组织结构为Al_2O_3/TiAl+Ti_3O_5/NiTi+Cu_3Ti+Ag(s,s)/Ag(s,s)+Cu(s,s)+(Cu,Ni)/Fe-Ni-Co。采用Ag-Cu-8Ti获得的钎焊接头的界面反应层与Ag-Cu-4Ti差异不大,但反应层稍微增厚,并伴有TiO和Ti_3Al在Al_2O_3/Ag-Cu-Ti界面生成。

Al2O3 ceramic/Fe-Ni-Co joints were achieved using Ag-Cu-Ti filler alloy to investigate the dependence of the joint microstructure and mechanical properties on the Ti content. Scanning electron microscope（SEM）, energy dispersive X-ray spectrometer（EDS）, X-ray diffractometer（XRD） and electronic universal testing machine were used to characterize the microstructure and mechanical properties of the joints. The results show that the increase of Ti content can obviously intensify the interaction between Al2O3 and Ag-Cu-Ti. A layer of Ti-Al and Ti-O products is observed at the interface of Al2O3/Ag-Cu-Ti. The tensile strength of Al2O3/Ag-Cu-Ti/Fe-Ni-Co joint increases as the Ti content increases from 2 wt% to 8 wt%, and the tensile strength of the brazing joint reaches the maximum value of 78 MPa. Good reaction layer is formed by metallurgical reaction at the interface of Al2O3/Ag-Cu-4 Ti, and the typical microstructure is Al2O3/TiAl＋Ti3O5/NiTi＋Cu3Ti＋Ag（s,s）/Ag（s,s）＋Cu（s,s）＋（Cu,Ni）/Fe-Ni-Co when brazed at 890 ℃ for 5 min. Compared with AgCu4Ti filler, the microstructure of the joints changes slightly when addition of the active element Ti to 8 wt% except for the increase of the thickness of reaction layer adjacent to Al2O3 ceramic, which is accompanied by the formation of TiO and Ti3Al in the Al2O3/Ag-Cu-Ti interface.