Investigation of mechanical properties and optimization of ultrasonic-assisted simple shear extrusion process using the response surface method

Abstract

This paper examines the mechanical performance and optimization of the Ultrasonic-Assisted Simple Shear Extrusion (USSE) process. Conventional severe plastic deformation (SPD) methods often suffer from high friction, elevated forming forces, and microstructural non-uniformity. However, the USSE method addresses these limitations by applying high-frequency ultrasonic vibrations. In this study, Finite Element Analysis (FEA) and the Response Surface Method (RSM) are used together to model the process and identify optimal operating conditions. Three main input parameters, punch speed, resonant frequency, and vibration amplitude, are evaluated for their influence on forming force and plastic strain. The findings indicate that vibration amplitude is the dominant factor, contributing 90.89% to forming force reduction and 82.41% to plastic strain enhancement. Increasing vibration amplitude and lowering punch speed effectively decrease forming force while promoting higher plastic strain. RSM optimization suggested the optimal conditions as a vibration amplitude of 30.11 µm, a punch speed of 0.61 mm/min, and a resonant frequency of 21.68 kHz. Under these conditions, the USSE process significantly reduced forming force and substantially increased plastic strain compared to the conventional SSE method. Surface roughness measurements showed that Specimen P4 exhibited 21%, 9%, and 6% lower roughness than P1, P2, and P3, respectively. Additionally, the optimized USSE sample demonstrated a 10% improvement in ultimate tensile strength and an 82% reduction in grain size relative to the SSE specimen. These outcomes confirm the effectiveness of the USSE technique and its superior mechanical and microstructural advantages.