TA15钛合金电子束焊缝形貌及其组织研究

采用不同工艺参数对TA15钛合金进行电子束焊接,通过观察焊缝形貌、测量其形状参数研究了焊接接头形貌的变化规律,并分析了焊接接头组织。结果表明:增大电子束流时,熔深、半熔深熔宽、焊缝宽度都增大,焊缝横截面的形状从"钉形"转变为"钟罩形";增大焊接速度,对焊缝形状影响不大,熔深、半熔深熔宽及焊缝宽度均减小,深宽比先增大后减小;聚焦电流的增大对熔深作用较明显,半熔深熔宽及焊缝宽度变化不大;扫描幅值的增加使焊缝熔深减小,半熔深熔宽增大。靠近母材的热影响区组织与母材组织相近,主要由初生等轴状α相及转变β相组成,并出现针状(α+β);靠近熔合线的组织由α相和针状(α+β)相构成,并出现α'马氏体;熔合区组织由α'组成,熔合线周围柱状晶垂直于焊缝中心生长,并在焊缝中心形成单列或多列的等轴状晶。

Study on the Morphology and Microstructure of TA15 Titanium Alloy EBW Welded Joint

In this article,TA15 titanium alloy was welded by electron beam welding with different process parameters,the morphology of welded joints were investigated by observing the morphology of the welded joints and measuring the shape parameters,and the microstructure of the welding joint was analyzed.The results show that the weld penetration,half of width and weld width increase when the electron current increases,and the weld shape changes from the nail shape to the bell shape.The welding speed has little effect on the weld shape,the weld penetration,half of width and weld width decreases with the increase of the welding speed,and the ratio of depth to width increases first and then decreases.The increase of focusing current has a large effect on the weld penetration,but the half of width and weld width change little.when the scanning amplitude increases,the weld penetration decreases,half of width increases.The heat affected zone (HAZ) near the base metal was similar to the base metal,Which was mainly composed of the primary equiaxed α phase and transformed β phase,and the acicular (α+β);The HAZ near the fusion line was consist of α phase and acicular (α+β),and appear α';the microstructure of fusion zone was α',the columnar crystals grew perpendicularly to the weld center,and single or multiple columns of equiaxed grain formed in the weld center.