Processing ultrafine grained non-circular cross-section profiles via severe plastic deformation

Abstract

In this study, a new technique is presented for processing ultrafine-grained noncircular thin section profiles via severe plastic deformation. For the first time, a noncircular thin section profiles can be severe plastic deformation processed by this method entitled the noncircular thin section cyclic extrusion–compression (NCTS-CEC). In this technique, the whole length of the profile is passed through a neck zone while it is fully enclosed by the tools set. Therefore, the whole length of the specimen experiences a cyclic extrusion and compression, which accumulates a high level of strain in the material. The feasibility of the NCTS-CEC was successfully examined on aluminum profiles with L, U, and hollow square cross-sections. The microstructure evolution of the processed specimens was investigated by metallographic observations and X-ray diffraction analysis, which demonstrate the formation of a ultrafine-grained microstructure after processing by two cycles of the NCTS-CEC. Moreover, evaluations of the mechanical properties of the processed profiles show remarkable improvements in the yield and ultimate strengths. The microhardness of the processed specimens was also increased after the second cycle to ∼55 Hv from the initial value of 30 Hv. The deformation behavior of the material during processing by the NCTS-CEC method was also numerically simulated by the commercial finite element software DEFORM TM-3D V11.

Effect of Strain Per Pass on Microstructure and Mechanical Properties of Multi-Axially Forged Cast AA5083 Alloy at Room Temperature

“…After 2 nd cycle hardness increased to 147±4.7 HV by almost 88% compared to the homogenized state. Increase in the hardness is attributed to the intensive strain hardening and grain refinement 23 .…”

A comprehensive comparison between the effect of elevated temperature constrained groove pressing on the microstructural evolutions, crystallographic texture, and mechanical properties of Al 2024 and Mg AZ91D alloys

“…1 In SPD operation, the microstructure of the workpiece is considerably modified such that the grain size can be reduced, and consequently, the mechanical properties of the material are significantly improved whereas the size of the component is unchanged. 2 This type of strengthening is carried out without the addition of alloying elements and/or ceramic particles. 3 During the past two decades, various SPD methods have been proposed by different researchers, among which the constrained groove pressing (CGP) technique is employed for increasing the strength of sheet metals.…”