Process and Mechanism of Sealing 65 vol.% SiCp/ZL102 Composite and DM305 Electronic Glass with Borosilicate Glass

Abstract

SiC-particulate-reinforced aluminum matrix composites (SiCp/Al MMCs) are widely used in the aerospace field due to their high specific stiffness and strength, low thermal expansion coefficient, and good radiation resistance. In the process of application and promotion, there is a connection problem between the aluminum matrix composites and electronic glass. In this work, the lead-free SiO2-B2O3-Na2O glass filler was used to seal 65 vol.% SiCp/ZL102 composites and DM305 electronic glass in an atmospheric environment. The effects of the sealing temperature on the properties of the joints were studied by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Additionally, the causes of defects and the fracture mechanisms of the joints were analyzed. The results showed that the glass filler and base material were connected through a dual mechanism of an Al, Na, Si, and O element diffusion reaction and a mechanical occlusion. At a sealing temperature of 540 °C and a holding time of 30 min, the joint interface was dense and crack-free. Meanwhile, the average shear strength reached 13.0 MPa, and the leakage rate of air tightness was 1 × 10−9 Pa·m3/s. The brittle fracture features were revealed by the step-like morphology of the fracture, which originated from the brazing seam and propagated into the pore. The crack gradually propagated into the base material on both sides as the fracture area expanded, ultimately resulting in a fracture.