【摘要】 铝锂合金激光焊接的熔凝过程存在晶界Cu偏析现象,对焊接接头组织形貌及腐蚀性能可能产生关键影响。本文采用激光熔凝技术在2098铝锂合金板材上获得熔凝组织。研究发现,2098铝锂合金激光熔凝组织上表面可以对称分为熔池中心的柱状晶区、熔池边缘的等轴晶区、介于熔池中心和熔池边缘之间的柱状晶区三个区域。由熔池心部到熔池边缘,晶界Cu偏析程度逐渐升高。激光扫速5mm/s时,熔池边缘的晶界Cu含量可达21 wt.%(质量分数),熔池心部的晶界Cu含量约为9 wt.%。熔凝组织的抗腐蚀能力随Cu偏析程度的增大而降低。更多还原

【Abstract】 Grain Boundary(GB) copper segregation is inevitable for Al-Li alloys during laser remelting. Copper segregation may significantly influence the microstructure and corrosion property of Al-Li alloys. In the present study,laser remelting technique was employed to obtain laser-remelted structure on 2098 Al-Li alloy. Scanning electron microscopy and energy dispersive spectroscopy were used to characterize the microstructure of laser remelted zone and the feature of copper segregation. Immersion test was conducted to analyze the corrosion behavior of laserremelted Al-Li alloy. It is found that the upper surface of laser-remelted Al-Li alloy can be symmetrically divided into three parts: the columnar grain zone in the center of the weld, equiaxed grain zone at the edge of welding pool, and columnar grain zone in between the center and the edge of the weld. The GB copper content increases from the center to the edge. With a laser scanning speed of 5 mm/s, the amount of GB copper content could reach to 21 wt.%,while it is around 9 wt.% at the center of the weld. The corrosion resistance of laser remelted Al-Li alloy declined with the increase of GB copper segregation.更多还原