%0 Journal Article
%T Microstructures and Hardness Prediction of an Ultrafine-Grained Al-2024 Alloy
%J Metals | An Open Access Journal from MDPI
%D 2019
%R https://doi.org/10.3390/met9111182
%X High-pressure torsion (HPT) is a high efficiency processing method for fabricating bulk ultrafine-grained metallic materials. This work investigates microstructures and evaluates the corresponding strengthening components in the center of HPT disks, where effective shear strains are very low. An Al-4.63Cu-1.51Mg (wt. %) alloy was processed by HPT for 5 rotations. Non-equilibrium grain and sub-grain boundaries were observed using scanning transmission electron microscopy in the center area of HPT disks. Solute co-cluster segregation at grain boundaries was found by energy dispersive spectrometry. Quantitative analysis of X-ray diffraction patterns showed that the average microstrain, crystalline size, and dislocation density were (1.32 ¡À 0.07) ¡Á 10£¿3, 61.9 ¡À 1.4 nm, and (2.58 ¡À 0.07) ¡Á 1014 m£¿2, respectively. The ultra-high average hardness increment was predicted on multiple mechanisms due to ultra-high dislocation densities, grain refinement, and co-cluster¨Cdefect complexes
%U https://www.mdpi.com/2075-4701/9/11/1182