AgCu+nano-Al2O3复合钎料钎焊TC4合金与Al2O3陶瓷：界面结构及接头性能

Brazing TC4 Alloy to Al2O3 Ceramic Using Nano-Al2O3 Reinforced AgCu

摘要:

通过向AgCu共晶钎料中添加nano-Al2O3增强相(2%, 质量分数)并采用高能球磨的方法获得了AgCu+nano-Al2O3复合钎料（AgCuC钎料）。采用AgCuC钎料实现了TC4合金与Al2O3陶瓷的高质量钎焊连接，确定了TC4/AgCuC/Al2O3钎焊接头的典型界面组织结构为：TC4/α-Ti+Ti2Cu扩散层/Ti3Cu4层/Ag(s,s)+Ti3Cu4+TiCu/Ti3Cu4层/Ti3(Cu,Al)3O层/Al2O3。Nano-Al2O3的添加抑制了钎缝中连续的Ti-Cu化合物层的生长，同时在钎缝中形成了颗粒状Ti-Cu化合物相增强的Ag基复合材料，改善了钎焊接头的界面组织。随着钎焊温度的升高，各反应层厚度逐渐增加，颗粒状Ti-Cu化合物不断长大，Ag基复合材料组织逐渐细小。当钎焊温度T=920 ℃，保温时间t=10 min时接头抗剪强度达到最大为67.8 MPa，典型断口分析表明：压剪过程中，裂纹起源于钎角处并沿钎缝扩展后转入Al2O3陶瓷，最终在Al2O3陶瓷母材侧发生断裂

Abstract:

A nano-Al2O3 reinforced AgCu composite filler (named AgCuC) was developed by introducing nano-Al2O3 (2 wt%) into AgCu eutectic powder filler and then by high-energy ball milling. High-quality brazing of TC4 alloy to Al2O3 ceramic was achieved using the AgCuC filler. The typical interfacial microstructure of TC4/AgCuC/Al2O3 joint was TC4/α-Ti+Ti2Cu diffusion layer/Ti3Cu4 reaction layer/Ag(s,s)+Ti3Cu4+TiCu/Ti3Cu4 reaction layer/Ti3(Cu,Al)3O reaction layer/Al2O3. The addition of nano-Al2O3 in AgCuC filler could improve the interfacial microstructure by constraining the growth of continuous Ti-Cu intermetallic layers. Moreover, granular Ti-Cu phases reinforced Ag based composite is formed in brazed joint. Both the thickness of reaction layers and the size of granular Ti-Cu phases increase with an increasing brazing temperature, while the content of Ag based composite decreases. The highest shear strength of 67.8 MPa is achieved when brazed at 920 °C for 10 min. Typical fracture analyses show that the crack originates in the fillet, extends along the brazing seam and then transforms into Al2O3 ceramic, and finally fractures in the Al2O3 substrate side