大厚度TC21钛合金电子束焊接试验

Electron beam welding of TC21 titanium alloy with large thickness

关键词:  TC21钛合金  电子束焊接  显微组织  力学性能

Key words:  TC21 titanium alloy  electron beam welding  microstructure  mechanical properties

摘要:

对56 mm厚TC21钛合金进行了电子束对接试验,对接头显微组织和力学性能进行了研究.结果表明,接头焊缝区组织形态以柱状β晶粒为基体,针状的马氏体弥散其中;热影响区从焊缝到母材分为三个区域,依次为等轴再结晶β晶粒区、片状和针状α相形成的魏氏组织区以及片状α相聚集长大的区域;熔合区内柱状晶与等轴晶联生.接头强度达到母材水平,断裂发生在母材内,接头厚度方向性能一致.接头塑性损失较大,只达到母材的50%左右.接头焊缝区硬度最高,其次是热影响区的等轴晶区和魏氏组织区,而热影响区内片状α相聚集长大的区域硬度值最低.

Abstract:

Electron beam welding of TC21 56 mm titanium alloy was carried out.The microstructure and the mechanical properties of welded joints were analyzed and tested.The results showed that the weld zone consisted of the columnar β grains, and in which the transgranular acicular α' martensite were dispersedly distributed.HAZ can be divided into three parts from base metal to weld zone, which are the equiaxed recrystallized β grain zone, Widmanstaten structure zone formed by lamellar and acicular α phases and lamellar α phase coarsening zone.Fusion zone consists of the adnate columnar and equiaxed grains.Tensile strength of joints reaches to that of base metal and the failure appears in the base metal.The mechanical properties are uniform along the vertical direction.Plasticity in the welded joint is greatly decreased and only up to 50% of that of the base metal.The microhardness in weld zone is the highest, and that of the equiaxed grain zone and Widmanstaten structure zone in HAZ is higher, and the microhardness in columnar α phase coarsening zone is the lowest.