【摘要】 采用柱形光头搅拌针搅拌摩擦焊接5mm厚的铝锂合金轧制板,并对接头组织和力学性能进行了分析。焊后接头形成了三个组织差异明显的区域:焊核区,热机影响区和热影响区。焊核区微观组织呈鱼鳞状;热影响区组织在焊接热循环作用下,发生回复反应,形成棒状的回复晶粒;前进侧和后退侧热机影响区内为颗粒较大的等轴晶晶粒,且后退侧晶粒尺寸大于前进侧。力学性能测试结果表明,焊接速度υ=40mm/min时,接头获得最高拉伸强度(296MPa);焊接速度υ=80mm/min时,接头获得最大延伸率(8.6%)。硬度测试结果表明,焊缝区发生了软化,前进侧和后退侧材料的软化区间大致相同,但后退侧软化程度高于前进侧。更多还原

【Abstract】 Friction stir welded 5 mm thick, Al-Li alloy rolled sheet, metallurgical, hardness and tensile strength measurements were performed. The results demonstrate that there exist three distinct zones in the FSW joint: the weld nugget zone (WNZ), and the thermal-mechanically affected zone (TMAZ), and the heat-affected zone (HAZ). The microstructures in WNZ take on scale shape. Under the thermal cycle, the microstructures in HAZ occur recovery and generate the bar-shape recovery structure. The microstructures in TMAZ consist of the equiaxed grains, and the grain size of the microstructures at the retreating side is bigger than that at the advancing side. The tensile test results confirm that the highest tensile strength of Al-Li FSW joints welded with a cylinder-shape and non-thread pin is 296MPa(under the welding speed υ =40mm/min), and the highest elongation percentage is 8.6%( under the welding speed υ =80mm/min).The hardness measurements show that the weld is softened, and the softened scope of both the advancing and the retreating sides are almost the same. But the soften degree of the material at the retreating side is higher than that at the retreating side.更多还原