Effects of grain size on mechanical properties of nanostructured copper alloy by severe plastic deformation (SPD) process

Purpose: Severe plastic deformation (SPD) has provided new opportunities in investigations of enhanced mechanical properties like high strength and ductility by permitting grain refinement to a nanometer level, especially ultra-fine grained and nanocrystalline metals and alloys. These materials have been attracting more and more research interest during the past few decades due to scientific curiosity and their engineering potentials with a significant advancement in their understanding. The purpose of this paper is to find the relationship between processing, structures and properties of these novel materials with the ultimate goal of producing a model to account for the grain size changes at the nano-scale. Design/methodology/approach: In this paper, specimens with various grain sizes from 23 to 80 μm are obtained via processing by SPD, using equal channel angular press (ECAP) technique. The effect of grain size on the hardness properties of nanostructured copper alloy has been investigated using micro-hardness testing of the samples to test the mechanical properties of this material. Findings: The results reveal that the copper alloys processed by SPD using ECAP technique after various passes differ in the grain size and mechanical properties. The hardness test exhibits grained size dependence according to Hall-Petch relationship from room temperature. The increase in the hardness with number of passages suggest increasing in strain during deformation, as the passes increase the smaller grain size can be produced. Originality/value: The paper usefully shows how nanostructured materials by SPD technique will offer a possible solution to the problem of using light metals for certain applications by increasing the strength of materials which could be used in structures where previously strength requirement in various industries, including such as, for example, transportation, medical devices and electronics. Understanding the relationship between processing, structures and properties will enhance the performance of metals and alloys in a target application which is important in improving the mechanical properties of engineering materials that are necessary fundamental for applications of lightweight materials and structures. The influences of structural parameters, such as grain size, grain shape on plastic deformation which is important parameters in study the mechanical properties of nanostructured materials.