# An Analysis of Mechanical Properties for Ultrasonically Welded Multiple C1220-Al1050 Layers
## 2 Experimental Procedure  
### Experimental Composition and Material  
Ultrasonic welding, as shown in Figure 1, is a process in which high-frequency vibrations of 20 kHz or higher are partially applied to the welding material to form a joint. When ultrasonic waves are used for welding metallic materials, they are applied in the lateral direction parallel to the material's surface, and when they are used for welding plastic materials, they are mainly applied in the longitudinal direction perpendicular to the material's surface [1; 2]. The ultrasonic metal welding system consists of a power supply, converter, booster, and horn, and by converting the electrical energy of 50-60 Hz coming from the power supply into mechanical vibration energy of 20-40 kHz through the converter, when the booster amplifies the micro-vibrations to be used in metal welding, the oxide film and the contaminated film on the metal surface are destroyed by the frictional heat generated by the vibration on the deposited metal through the horn, thus forming a metallic bond [22; 23].  
The ultrasonic welder used in the experiment, as shown in Figure 2, was a Komax 2050 model with a frequency characteristic of 20 kHz. There are three major variations in welding conditions through the controller, which are the welding time, welding force, and ultrasonic wave output strength. Two non-ferrous materials were prepared for this experiment, which are industrial grade pure metal (purity 99.0%-99.9%) 1000 series aluminum non-heat treatable alloy, and phosphorus deoxidized copper. The 1000 series aluminum alloys have a relatively weaker mechanical strength than other aluminum alloys, but are mainly used as wrought alloy because they have good corrosion resistance, light reflectivity, electrical and thermal conductivity, and excellent workability and weldability. The phosphorus deoxidized copper contains 0.015%-0.040% residual phosphorus (P), shows a uniform microstructure compared to oxygen-free copper, and has excellent ductility and fatigue strength and good weldability. The mechanical properties of the materials used in the experiment are shown in Table 1.  
In this study, 20 mm \(\times\) 100 mm \(\times\) 0.4 t specimens, as shown in Figure 3, were used for lap joint welding; these specimens were also used to evaluate the strength of weld after the experiment was  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Material**} & **Density** & **Modulus of** & & **Ultimate Tensile** & \\  & **(g/cm\({}^{3}\))** & **Elasticity** & **Poisson’s Ratio** & **Strength** & **Yield Strength** \\  & **(GPa)** & **(MPa)** & **(MPa)** & **(MPa)** & **(MPa)** \\ \hline
**Al (A1050)** & 2.71 & 68 & 0.30 & 138.3 & 125.5 \\
**Cu (C1220)** & 8.94 & 117 & 0.38 & 266 & 246 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Mechanical properties of base metal.  
Figure 2: Ultrasonic metal welding systems employed in experiment. (**a**) Systems configuration; (**b**) pattern shape on horn.  
Figure 1: Ultrasonic welding process.  
completed. The experiment was performed in two groups with a total of 25 welding conditions. The base materials used in the experiment were aluminum 1050 series and copper 1220 series. A total of four layers were formed for multi-layer dissimilar metal welding, and the aluminum and copper were arranged to cross each other. There are two types of specimens produced through the experiment. As shown in Figure 3a, the experiment with four specimens stacked up in a uniform arrangement was designed to simultaneously tension the four specimens, and in Figure 3b, the specimen was prepared to measure the shear strength by level in order to obtain the strength of each weld individually. A total of (\(25\times 2=50\)) experiments were conducted twice using 25 experimental conditions. The surfaces to be welded were cleaned in the order of stainless wire-brush, then sand paper--#400, #800, and #1500, to prevent foreign substances such as rust, scale, and oxides from causing weld defects.