Microstructure and mechanical properties of electron beam welded joints in different state of TC4

This paper studied the influence of a specification of electron beam welding on the structure of ‘rolled+ laser deposited’ TC4 welded joints, and analyzed the mechanical properties of the joints. Results show that on the rolled side, the microstructure of heat affected zone changes obviously, the shorter the distance away from welding center, the more amount of transformed β generates, and the columnar grain gradually transforms into equiaxed grain, with the appearance of clustered martensite α'. However, on the laser-deposited side, few changes are observed in the heat affected zone, β grain stays columnar, in which martensite α' generates, no equiaxed grain generates. The change trend of microhardness on both sides is similar, the closer the distance from the center, the higher the microhardness gets, the maximum hardness is around 400 HV found in the fusion zone. The mechanical properties of welded joints are similar to forged TC4, all the fractures locate in the laser-deposited base metal region.