填充泡沫 Ti/AlSiMg 复合钎料的 70% SiC_p/Al 复合材料钎焊接头组织性能研究

Aiming at the poor processability of the high-volume SiC_p/Al composites, the brazing of 70% SiC_p/Al composites with Ti foam/AlSiMg composite filler metal has been studied. The effects of brazing temperature, holding time and welding pressure on the microstructures and properties are investigated. The results show that the joint having the maximum shear strength of 119 MPa is brazed at 700 ℃, 60 min and 10 MPa. The fracture occurs on the composites, and there are a large number of dimples in the fracture surface which shows the characteristics of ductile fracture. Ti₇Al₅Si₁₂ can generate at not less than 650 ℃. The holding time has a certain influence on the joints’ microstructure. Ti₇Al₅Si₁₂ preferentially forms at the interface, and then Ti(Al, Si)₃ generates. Ti₇Al₅Si₁₂ tends to be broken and loose with the continuation of the insulation process. The joint kept for 60 min at 700 ℃ has the maximum shear strength, whose interface structure is “Composite/Ti₇Al₅Si₁₂/mixed layer/Ti₇Al₅Si₁₂/Composite”. The brazing pressure does not affect the microstructure of the joints, but it affects thickness, density and bonding strength. It can improve the mechanical properties of the joints by increasing the pressure under the condition of ensuring the integrity of the workpieces.