铝合金脉冲激光焊Mg元素烧损行为及接头硬度分布

采用Nd:YAG脉冲激光对1mm厚5A05铝合金板进行焊接,结合激光焊物理过程,研究和分析了焊接工艺参数(脉冲能量、脉冲宽度、焊接速度和离焦量)对Mg元素烧损和焊缝熔深的影响,以及焊缝中Mg元素含量的变化和接头的硬度分布.结果表明,Mg元素烧损受熔池搅拌作用的影响,随搅拌作用增强和焊缝熔深的增加,焊缝中Mg元素烧损率减小;受Mg元素含量和冷却速度影响,焊接接头硬度在熔合线附近具有最大值,在焊缝中从表面到熔池底部硬度先减小再增大.

Evaporation loss of Mg element in pulsed laser welding of 5A05 aluminum alloy and distribution of micro-hardness of welding joint

5A05 aluminum alloy plate with the thickness of 1 mm was welded with Nd; YAG laser beam. The effect of welding parameters including pulse energy, pulse duration, welding speed and defocusing distance on the evaporation loss of Mg element, depth of fusion, variation of Mg element content in weld metal and micro-hardness of weld-joint were studied and analyzed. The results showed that stirring in molten pool had a significant effect on the evaporation loss of Mg element. With the increase of stirring and the weld penetration, the evaporation loss of Mg element was decreased. Due to the effect of Mg element content and cooling rate, the maximum hardness of weld joint was approximately located at the fusion line. From the surface to the bottom of molten pool, the hardness of weld joint first decrease and then increase.