In response to the continuous demand for industry progress and the need for low-cost alternative materials that have superior properties than the present ones, a new coupling agent was used to treat composites, which were used as new backing materials in ultrasonic array transducers. In array transducers, back-echo reverberation to the piezoelectric elements occurs, so backing materials are critical in reducing these echoes. The Cu–Al–Zn-alloy was treated with a coupling agent before being incorporated into ethylene propylene diene monomer (EPDM) composites. Cu–Al–Zn-alloy/EPDM composites were assessed using rheometric, mechanical, and morphological properties. The division of cu-alloy at the EPDM matrix was visualized using a scanning electron microscope (SEM). TGA and DSC techniques were used to study the thermal characterization of the EPDM composites. As a result, the treated Cu-alloy improved the thermal, mechanical, and morphological characteristics of EPDM composites. Ultrasonic measurements ensured the composites' effectiveness as backing materials in ultrasonic array transducers. Furthermore, the composites’ properties were similar to those of the most commonly used epoxy/tungsten backing material. Finally, linear ultrasonic-phased array transducers were fabricated using Cu–Al–Zn-alloy/EPDM composites. They had a low signal-to-noise ratio, and this ensured the effectiveness of Cu–Al–Zn-alloy/EPDM composites as backing materials.