A Comparative Study of Microstructure and Mechanical Properties in Copper Processed by Simple Shear Extrusion and Elliptical Cross-Section Spiral Equal-Channel Extrusion

Balali, Mostafa

doi:10.30501/acp.2026.584598.1197

A Comparative Study of Microstructure and Mechanical Properties in Copper Processed by Simple Shear Extrusion and Elliptical Cross-Section Spiral Equal-Channel Extrusion

Document Type : Original Research Article

Author

Mostafa Balali

Instructor, Department of Mechanical Engineering, Hakim Sabzevari University, Sabzevar, Iran.

10.30501/acp.2026.584598.1197

Abstract

One of the well-known approaches for producing ultrafine-grained and nanostructured materials is severe plastic deformation (SPD), which has attracted significant attention in recent years. This study investigates the microstructural evolution and mechanical properties of commercially pure copper processed by two SPD methods: Simple Shear Extrusion (SSE) and Spiral Equal-Channel Extrusion with an Elliptical Cross-Section (ECSEE). Samples underwent four sequential extrusion passes at room temperature using both techniques and were subsequently characterized through metallography, microhardness measurements, tensile testing, and forming force analysis. The results demonstrate a substantial enhancement in mechanical properties and grain refinement with each additional pass for both processes. However, the ECSEE method, which imposes more severe plastic strain, yielded superior results. Specifically, after four passes, the ECSEE-processed samples achieved an ultimate tensile strength of 349 MPa and a microhardness of 166 HV, representing increases of 104% and 9%, respectively, compared to the annealed condition. In contrast, the SSE method, which applies lower and more gradual strain, resulted in an ultimate tensile strength of 242 MPa and a microhardness of 139 HV after four passes. Microstructural analysis revealed reductions in grain size of 28% and 17% for the ECSEE- and SSE-processed samples, respectively, after the fourth pass. Furthermore, the SSE method required a lower forming force due to the lower strain imposed. The findings conclusively indicate that the ECSEE process produces superior microstructural characteristics and enhanced mechanical behavior, including strength, microhardness, and ductility, compared to the SSE method.

Keywords

Severe Plastic Deformation

Simple Shear Extrusion

Elliptical Cross-Section Spiral Equal Channel Extrusion

Mechanical Properties

Microstructural Properties

Subjects

Nanomaterials and Nanostructures

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