Decreasing welding energy input with enhanced welding quality is difficult to achieve in ultrasonic welding. In this study, a nanoparticle-accelerated ultrasonic welding technique using a Cu nanoparticle (Cu NP) interlayer was proposed. Lap shear tests revealed that the addition of Cu NPs drastically increased the load carry capacity by 253 % for Cu-Cu joints welded with an ultrasonic energy as low as 200 J, reducing the energy input to half of that without Cu NPs. This low energy requirement was attributed to the increase in peak temperature. The clamping force drove Cu NPs to fill and sinter in the interfacial gaps, which also significantly reduced the welding energy required for intimate contact in the early stage of welding. Furthermore, severe plastic deformation, enhanced friction, and nanosized grains induced by the Cu NPs facilitated material flow, accelerated elemental diffusion, and grain refinement at the interface. The enhancement of dynamic recrystallization in the base metal caused by the Cu NPs was confirmed by the calculated Zener-Hollomon parameter and critical recrystallization strain.

在超声波焊接中，难以实现降低焊接能量输入，提高焊接质量的效果。在这项研究中，提出了一种使用Cu纳米粒子（Cu NP）夹层的纳米粒子加速超声焊接技术。搭接剪切试验表明，对于使用低至200 J的超声波能量焊接的Cu-Cu接头，添加Cu NP可以使承载能力大幅提高253％，从而将能量输入降低为不使用Cu NP的能量输入的一半。较低的能量需求归因于峰值温度的升高。夹紧力驱使铜纳米颗粒在界面间隙中填充并烧结，这也大大降低了焊接初期紧密接触所需的焊接能量。此外，严重的塑性变形，增强的摩擦力，Cu NPs诱导的纳米晶粒促进了材料流动，加速了元素扩散以及界面处的晶粒细化。计算出的Zener-Hollomon参数和临界再结晶应变证实了Cu NPs引起的贱金属动态再结晶的增强。