Ultrasonic additive manufacturing (UAM) is a novel solid‐state freeform fabrication process that utilizes ultrasonic energy to merge similar/dissimilar metal tapes. Metallurgical bonding between the metal tapes can be achieved instantaneously once the sonotrode rotates through. Herein, five‐layered Al‐1100 ultrasonically consolidated samples are fabricated under various parameter combinations of ultrasonic amplitude and normal force settings. The microstructure and texture evolution of the built component among layers are characterized using electron backscattered diffraction (EBSD). The results reveal that among the upper layers, recrystallization only occurs at very local interface regions due to the local shear deformation, while the bulk region of each layer still remains the starting microstructure unaffected. However, after this cyclic accumulating process, dynamic recovery (DRV) and dynamic recrystallization (DRX) are observed to take place in the bottom of the built samples. The evolution of microstructures and textures of the bottom layer is a function of input energy, which well explains the effect of ultrasonic energy on the microstructure evolution at the metallurgical bonding regions.

中文翻译：

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超高功率超声增材制造中的动态重结晶和恢复

超声增材制造（UAM）是一种新颖的固态自由形式制造工艺，该工艺利用超声能量合并相似/不相似的金属带。一旦超声波发生器旋转通过，即可立即实现金属带之间的冶金结合。在此，在超声振幅和法向力设置的各种参数组合下制造了五层Al-1100超声固结样品。使用电子背散射衍射（EBSD）可以表征各层之间构建组件的微观结构和纹理演变。结果表明，在上层之间，由于局部剪切变形，仅在非常局部的界面区域发生再结晶，而每层的大部分区域仍保持初始微观结构不受影响。然而，在循环累积过程之后，观察到动态恢复（DRV）和动态重结晶（DRX）在生成的样品的底部发生。底层的微观结构和织构的演变是输入能量的函数，这很好地解释了超声能对冶金结合区微观组织演变的影响。