Microstructure and interracial reactions of Al2O3 joints brazed with Al2O3-particulate-contained composite Ag-Cu-Ti filler material were researched by scanning electron microscopy （SEM）, electron probe microscopy an...Microstructure and interracial reactions of Al2O3 joints brazed with Al2O3-particulate-contained composite Ag-Cu-Ti filler material were researched by scanning electron microscopy （SEM）, electron probe microscopy analysis （EPMA）, energy dispersive spectroscopy （EDS） and X-ray diffraction （XRD）. The interracial reaction layer thickness of joints brazed with conventional active filler metal and active composite filler materials with different volume fraction of Al2O3 particulate was also studied. The experimental results indicated although there were Al2O3 particulates added into active filler metals, the time dependence of interracial layer growth of joints brazed with active composite filler material is t^1/2 as described by Fickian law as the joints brazed with conventional active filler metal.展开更多
为改善紫铜与Al_2O_3陶瓷的连接强度,采用纳米-Al_2O_3增强的AgCuTi复合钎料(Ag Cu Tip)对紫铜与Al_2O_3陶瓷进行了真空钎焊.采用扫描电镜、能谱分析以及剪切试验对钎焊接头微观组织及力学性能进行了分析.钎焊接头典型界面组织为紫铜/...为改善紫铜与Al_2O_3陶瓷的连接强度,采用纳米-Al_2O_3增强的AgCuTi复合钎料(Ag Cu Tip)对紫铜与Al_2O_3陶瓷进行了真空钎焊.采用扫描电镜、能谱分析以及剪切试验对钎焊接头微观组织及力学性能进行了分析.钎焊接头典型界面组织为紫铜/扩散层/铜基固溶体+银基固溶体+Ti_2Cu+Ti_3(Cu,Al)3O/Al_2O_3.纳米-Al_2O_3的添加抑制了Al_2O_3侧反应层的生长,并促进钎缝中形成弥散分布的Ti_2Cu相.随着保温时间的延长,铜侧扩散层和Ti_3(Cu,Al)_3O反应层的厚度逐渐增大.保温时间为20 min时,铜母材向钎料过度溶解,降低了接头性能.当钎焊温度为880°C,保温10 min时,接头抗剪强度最高为82 MPa.纳米颗粒的加入细化了钎缝组织并降低了母材与钎缝热膨胀系数的不匹配,因此提高了接头的连接性能.保温时间可影响界面组织及反应层的厚度,进而影响接头的连接强度.展开更多
Development of the technological process for brazing of heat-resistant copper alloy strengthened with Al2O3 oxide particles is an important task of fabrication of high-temperature application structures. As mechanical...Development of the technological process for brazing of heat-resistant copper alloy strengthened with Al2O3 oxide particles is an important task of fabrication of high-temperature application structures. As mechanical properties of the brazed joints directly depend on the structural factor and morphological peculiarities of the brazed seams, the latter are of technological interest in terms of making of permanent joints. This study gives results of X-ray spectral microanalysis of the brazed joints on dispersion-strengthened copper alloy （ Gridcop Al-25 ） produced by using the Ti-Cu system adhesion-active brazing filler alloy, different heat sources and temperature-time parameters of the brazing process. Shown are differences in formation of structure of the seams made by vacuum brazing using radiation and high-frequency heating. Vacuum brazing with radiation heating provides the homogeneous seams with crystallisation of the phases based on the CuTi and CuTi2 compounds in the form of discrete faceted particles 2 - 9μm in size against the background of the copper matrix. Based on investigation of structural peculiarities of the brazed seams, the temperature-time conditions of vacuum brazing with radiation heating were selected for manufacture of specimens for mechanical tests. Analysis of the results of strength tests of the butt brazed specimens proved the expediency of preliminary heat treatment of the base material, providing strength of the joints at a level of about 92% of that of the base material.展开更多
基金the National Natural Science Foundation of China(Grant No.50075019) the Visiting Scholar Foundation of Key Lab.in University of China
文摘Microstructure and interracial reactions of Al2O3 joints brazed with Al2O3-particulate-contained composite Ag-Cu-Ti filler material were researched by scanning electron microscopy （SEM）, electron probe microscopy analysis （EPMA）, energy dispersive spectroscopy （EDS） and X-ray diffraction （XRD）. The interracial reaction layer thickness of joints brazed with conventional active filler metal and active composite filler materials with different volume fraction of Al2O3 particulate was also studied. The experimental results indicated although there were Al2O3 particulates added into active filler metals, the time dependence of interracial layer growth of joints brazed with active composite filler material is t^1/2 as described by Fickian law as the joints brazed with conventional active filler metal.
文摘Development of the technological process for brazing of heat-resistant copper alloy strengthened with Al2O3 oxide particles is an important task of fabrication of high-temperature application structures. As mechanical properties of the brazed joints directly depend on the structural factor and morphological peculiarities of the brazed seams, the latter are of technological interest in terms of making of permanent joints. This study gives results of X-ray spectral microanalysis of the brazed joints on dispersion-strengthened copper alloy （ Gridcop Al-25 ） produced by using the Ti-Cu system adhesion-active brazing filler alloy, different heat sources and temperature-time parameters of the brazing process. Shown are differences in formation of structure of the seams made by vacuum brazing using radiation and high-frequency heating. Vacuum brazing with radiation heating provides the homogeneous seams with crystallisation of the phases based on the CuTi and CuTi2 compounds in the form of discrete faceted particles 2 - 9μm in size against the background of the copper matrix. Based on investigation of structural peculiarities of the brazed seams, the temperature-time conditions of vacuum brazing with radiation heating were selected for manufacture of specimens for mechanical tests. Analysis of the results of strength tests of the butt brazed specimens proved the expediency of preliminary heat treatment of the base material, providing strength of the joints at a level of about 92% of that of the base material.
