工业纯锆焊缝金相组织和力学性能

为了研究工业纯锆在焊缝不同区域的分布、金相组织和力学性能之间的关系，采用TIG方法焊接锆R60702工业纯锆板对接焊缝，采用光学显微镜、电子探针和显微硬度计等仪器，分析焊缝母材区、热影响区、熔合区和焊缝区的金相组织、机械性能和元素分布特性.研究结果表明:对接接头各区域的组织不同，母材区的晶粒为等轴状，呈面织构；不完全重结晶区的晶粒亦为等轴状，而且更细于母材晶粒，因而强度、塑性优良；过热区的晶粒则较粗大；焊缝区组织为铸态晶粒，形状为纤维状；对接接头各区的元素分布较为均匀，没有明显的偏析现象；焊接接头的硬度呈W型分布，最高硬度分布在焊缝区达到290 HV50 g，最低硬度分布在不完全重结晶区，达到162 HV50 g，过热区则介于母材区与焊缝区之间. 

Metallurgical Structure and Mechanical Properties Test of Weld-Joint of Industrial Pure Zirconium

The element distribution, metallurgical structure and mechanical properties in different parts as base-zone, heat-treatment zone, and welded seam in butt-jointed seam of industrial pure zirconium R60702 welded with TIG was analyzed using optical microscope, electron probe and micro-hardness tester to study the relationship of microstructure and mechanical properties. The results show that different zones of the butt-jointed seam have different metallurgical structures: the crystalline grains in the base metal are equiaxed and surface textured; smaller and equiaxed grains in incomplete recrystallization zone create better mechanical properties in strength and plasticity; coarse grains are found in over-heated zone; and the casting organization with fibre structure is obtained in welded seam zone. The elements distribute uniformly in the butt-welded seam without obvious segregation. The hardness distribution in the butt-jointed seam between the base metal to the welded seam zone is depicted as W-shape: the maximum micro-hardness reaches 290 HV50 g at the position of welded seam, the minimum harness is located in the overheated zone with a value of 162 HV50 g, and the hardness of over-heated zone fall in between.