Nd:YAG laser welding technology and microstructure of Be/Al-Mg alloy

Beryllium and A1-Mg alloy was welded by Nd: YAG laser. The reasonable welding parameter was obtained. The microstructure of beryllium and A1-Mg welding seam was analysed by means of X-ray energy spectrum, scanning electron microscope and electron probe microanalysis. The microstructure of welding seam is affected by cooling rates. The microstructure of welds consists of dendritic structure near melted line and equiaxed grain at the centerline of welding seam. Hot cracking and inclusion are main defects. These inclusions are formed by C, O, Al, Mg, F and C1 elements. The results of surface scanning show that C and 0 elements segregation exist surface layer of welding seam, on the other hand distribution of Mg and Be is uniformity. (authors)