Study On Pressure-assisted Electron Beam Welding SiC_p/Al Composites Technology

SiC_p/Al joints’ appearances are usually poor under welding methods such asElectron Beam Welding （EBW）, besides, there are brittle phases formed in the weld,which result in joints’ poor performance. To solve the problem, this paper proposeda "pressure-assisted-EBW" process to weld vol.45%-SiC_p/Al. The process consistsof "pressure-assisted-EB diffusion bonding" and "pressure-assisted-interlayer EBwelding". Meanwhile, ANSYS software is used to simulate welding process fordesigning experimental parameters.EB fusion weld consist of large granular SiC, Al₄C₃acicular phase, primary Sibulk and a little Al₂Cu IMC. Al₄C₃, Si generated from "Interfacial reaction" andgrown SiC result in weld embrittlement. Meanwhile, over melting of Al matrix leadto poor joints’ appearances. Hence, SiC_p/Al joints’ mechanical performances areunsatisfying."Pressure-assisted-EB diffusion bonding" successfully avoided the generationof Al₄C₃, primary Si and SiC growth. Expectant diffusion bonding weld is obtained.The average tensile strength of diffusion bonding weld is65.45MPa, which isequivalent to that of the "EB fusion welding". And the joints’ appearance issignificantly better than that of EB fusion welding. But "SiC-SiC contact" and"cratering connection" in the weld interface affect the interface connection."Pressure-assisted-interlayer EB welding" acquire the SiC_p/Al joint that hasfine appearance and superior mechanical performance. Study shows excellent jointinterface can be formed between active interlayer Ti and SiC, meanwhile Al₄C₃andSi are avoided because of Ti presence. In addition, in situ formed Al3Ti, TiC andTi5Si4disperse in the weld as secondary reinforcements to enhance joints’mechanical properties. The joints’ average tensile strength reaches154MPa, whichis63%the strength of the base material. Compared with the EB fusion weld and the"diffusion bonding" weld, joints’ strength of “interlayer EB welding” has greatlyimproved.