轧制+增材TC4合金电子束焊接接头组织与性能

研究了一种电子束焊接规范对轧制+增材TC4钛合金焊接接头组织影响，分析了焊后钛合金力学性能.结果表明，轧制侧热影响区合金组织变化较大，离焊缝中心距离越近，β转变组织含量增加，晶粒逐渐转变为等轴晶组织，等轴晶内有集束状马氏体α'相析出，越靠近焊缝等轴晶尺寸越大；增材侧热影响区组织形态变化较小，β晶粒形态保持柱状晶形态，无等轴晶区产生，晶内组织转变为马氏体α'相.焊缝两侧热影响区显微硬度变化趋势相同，均为越靠近焊缝中心，显微硬度越高，焊接重熔区硬度最高，达400 HV左右.焊接接头力学性能与TC4钛合金锻件相当，且断裂位置均位于激光沉积母材区域.

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.