The Effect of Post-grinding Heat Treatment of Alumina and Ag-Cu-Ti Braze Preform Thickness on the Microstructure and Mechanical Properties of Alumina-to-Alumina-Brazed Joints

详细信息    查看全文

• 作者：Tahsin Ali Kassam ; Hari Babu Nadendla…
• 关键词：advanced ceramics ; alumina ; brazing ; heat treatment ; joining ; joint strength ; preform thickness ; TICUSIL®
• 刊名：Journal of Materials Engineering and Performance
• 出版年：2016
• 出版时间：August 2016
• 年：2016
• 卷：25
• 期：8
• 页码：3218-3230
• 全文大小：3,632 KB
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Chemistry
  Characterization and Evaluation Materials
  Materials Science
  Tribology, Corrosion and Coatings
  Quality Control, Reliability, Safety and Risk
  Engineering Design
  
• 出版者：Springer New York
• ISSN：1544-1024
• 卷排序：25

文摘

Alumina-to-alumina-brazed joints were formed using 96.0 and 99.7 wt.% Al₂O₃ and TICUSIL® (68.8Ag-26.7Cu-4.5Ti wt.%) preforms of different thicknesses. Brazing was conducted in a vacuum of 1 × 10−5 mbar at 850 °C for 10 minutes. Joint strengths were evaluated using four-point bend testing and were compared to flexural strengths of standard test bars. Post-grinding heat treatment, performed at 1550 °C for 1 hour, did not affect the average surface roughness or grain size of either grades of alumina but affected their average flexural strengths with a small increase for 96.0 wt.% Al₂O₃ and a small decrease for 99.7 wt.% Al₂O₃. As the TICUSIL® preform thickness was increased from 50 to 100 µm, the average strengths of both 96.0 and 99.7 wt.% Al₂O₃ brazed joints improved. Joints made using 100-µm-thick TICUSIL® preforms predominantly consisted of Cu-Ti phases which formed due to excess Ti in the interlayers and non-uniform Ag-rich outflow. Brazed joints of 96.0 wt.% Al₂O₃ made using 100-µm-thick TICUSIL® preforms achieved an average joint strength of 238 MPa with consistent failure in the ceramic.