Microstructure and mechanical properties evolution of AA 2024 alloy subjected to RCS

Abstract

This work has been aimed to evaluate the ability of repetitive corrugation and straightening (RCS) technique in fabricating ultra-fine grained Al-Cu alloy as well as to determine the hardness and microstructural evolution and its influence on grain size refinement. Aluminium alloy (AA-2024) has been successfully subjected to repetitive corrugation and straightening (RCS) up to 8 passes at room temperature. The influence of rotation of sample between each pass has been studied. The improved mechanical properties have been observed for the samples which have been rotated during each RCS pass. The grain refinement results clearly demonstrate that an average grain size of α-Al has been reduced 0.7 microns after 8 pass RCS from 30 microns of as cast condition sample. Similarly, the tensile strength has also been increased (8 pass RCS processed) to 265 MPa from 140 MPa (as cast condition). The improved mechanical properties are basically due to the grain refinement effect due to RCS and presence of fine Al2Cu precipitates. Thus, it is demonstrated that RCS as a promising new method for producing ultra-fine grained Al alloys. As a result, development of new Al alloys with unique mechanical properties has in great demand in aerospace sector. This paper contributes to the mechanical properties of Al-Cu alloy with Al2Cu precipitates strengthened ultra-fine grain size subjected to RCS method.