Evolution of the bulk microstructure in 1100 aluminum builds fabricated by ultrasonic metal welding

The annealed 1100 aluminum foils were welded at room temperature with an ultrasonic metal welding (UMW) method. Effects of two key parameters (the oscillation amplitude and the deformation reduction of the welded foils) on the microstructural evolution were investigated. With the increase of oscillation amplitude, the deformation and the grain refinement of the foils in the welded specimen were homogeneous, but the grain size was not less than 25 mu m. With the increase of deformation reduction, the microstructures were inhomogenously changed from the initial coarse grains (45 mu m) into the dynamically recrystallized fine grains (2 mu m) in the upper foil, but they changed little in the lower foil. For both cases, the microstructural evolutions attributed to the grains and/or sub-grains rotation. The dynamic recovery and the followed continuous dynamic recrystallization were the active deformation mechanism during UMW according to the observation of the thermal and the deformation textures. The effects of both ultrasonic amplitude and deformation reduction on the hardness of the builds were measured. (C) 2013 Elsevier B.V. All rights reserved.

采用超声金属焊接（UMW）方法在室温下对退火态的1100铝箔进行焊接。研究了两个关键参数（振动幅度和焊接箔材的变形量）对微观结构演变的影响。随着振动幅度的增加，焊接试样中箔材的变形和晶粒细化是均匀的，但晶粒尺寸不小于25微米。随着变形量的增加，微观结构在上层箔材中从初始的粗大晶粒（45微米）不均匀地转变为动态再结晶的细小晶粒（2微米），而在下层箔材中变化较小。在这两种情况下，微观结构的演变归因于晶粒和/或亚晶粒的旋转。根据热织构和变形织构的观察，动态回复以及随后的连续动态再结晶是超声金属焊接过程中的主要变形机制。测量了超声振幅和变形量对焊件硬度的影响。（C）2013爱思唯尔有限公司保留所有权利。