The invention discloses an aluminum
alloy complex cavity
diffusion welding method, which is characterized in that a uniform and compact organic
molecule adsorption protection layer is formed on the surface of aluminum by completely immersing a cleaned blank in a
diethylene glycol dimethyl ether solution for ultrasonic-assisted treatment. The protective film can effectively isolate air at normal temperature and prevent the oxidation film from regenerating; and in the initial stage of
diffusion welding temperature rise, the aluminum
alloy can be completely decomposed and volatilized, no
impurity is left, and the high-activity clean aluminum surface is exposed. According to the method,
diffusion welding is carried out under the conditions that the vacuum degree is high, the temperature is 500-560 DEG C and the pressure is 5-15 MPa in cooperation with a positioning tool
system matched with the
thermal expansion coefficient, aluminum atoms are fully diffused under the condition that no oxidation film hinders exist, and high-quality metallurgical bonding is formed. By means of the technical scheme, the problem that the welding rate is low due to an oxidation film on the surface of the aluminum
alloy is successfully solved, meanwhile, the defects of ultrahigh vacuum equipment input and middle layer material introduction are overcome, and the
manufacturing quality and production efficiency of complex aluminum alloy components are greatly improved.