Laser beam welding of 2-mm-thick sheets of the Ti-6Al-4V alloy is reported in this paper. Different combinations of processing parameters (shielding gas, laser beam power, focal position, welding speed) were used. The laser welding parameters have been correlated with macrostructure and microstructure of welded joints, their microhardness, and to tensile properties of the welded material as well as the weld joints themselves. It has been determined that argon as a shielding gas is more preferable than helium. For the manufacturing of the weld joints with good penetration and geometry, at least a 42.75 J/mm of heat input into the material should be introduced. In this case, the weld joint has fine microstructure containing acicular martensite and small amount of remaining β-phase, and both the weld joint and the base material manifest good mechanical properties. Undesirable microstructural coarsening and deterioration of mechanical properties of welded material occur when that optimal heat input to the material is too much exceeded.

中文翻译：

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盘状激光焊接Ti-6Al-4V合金接头的组织和力学性能研究

本文报道了2mm厚的Ti-6Al-4V合金的激光束焊接。使用了加工参数（保护气体，激光束功率，焦点位置，焊接速度）的不同组合。激光焊接参数已与焊接接头的宏观结构和微观结构，其显微硬度，焊接材料的拉伸性能以及焊接接头本身相关联。已经确定，作为保护气体的氩气比氦气更优选。为了制造具有良好熔深和几何形状的焊接接头，应引入至少42.75 J / mm的热量输入材料。在这种情况下，焊接接头的组织微细，含有针状马氏体和少量残留的β相，焊接接头和基础材料都具有良好的机械性能。当过多地输入到材料的最佳热量输入时，会发生不希望的显微组织粗化和焊接材料的机械性能下降。