Electron beam welding of aluminium-beryllium-magnesium system alloy

Experimentally studied was the effect of the conditions of vaporization of a metal in the fusion zone and that of the variation of the chemical composition of the said metal upon the character of formation and the mechanical properties of the weld with a view to eliminate defects in joints of the Al-30Be-5Mg alloy welded by the electron-beam technique. Experiments have shown that the ratios of vapour components change as a function of the duration of electron-beam vacuum fusion of samples of the Al-3OBe-5Mg alloy. The increase in the time of existence of welding pool lowers the concentration of magnesium in the melt, and thus minimizes its adverse effect upon weld formation. This was achieved by using electron beam oscillations at frequencies of 50 to 100 Hz, and amplitudes of 3 to 4 mm in longitudinal and in longitudinal-transversal directions. It has been established that the introduction of a filler of an aluminium alloy containing not more than 3.5% Mg into the butt joint eliminates internal discontinuities in the form of pores or blue holes when the amount of the said filler in the weld is not less than 45%. Mechanical properties of welded joints are the best when the filler is the AK8 alloy