Dynamic deformation and fracture behavior of ultrafine-grained aluminum alloy fabricates by equal-channel angular pressing |
| |
Authors: | Yang Gon Kim Byoungchul Hwang Sunghak Lee Woo Gyeom Kim Dong Hyuk Shin |
| |
Affiliation: | (1) the Center for Advanced Aerospace Materials, Pohang University of Science and Technology, 790-784 Pohang, Korea;(2) the Department of Metallurgy and Materials Science, Hanyang University, 425-791 Ansan, Korea |
| |
Abstract: | In the present study, ultrafine-grained microstructures of a conventional 5083 aluminum alloy were fabricated by equal-channel
angular pressing, and their dynamic deformation and fracture behavior were investigated. Dynamic torsional tests were conducted
on four aluminum alloy specimens using a torsional Kolsky bar, and then the test data were analyzed in relation to microstructures,
tensile properties, and adiabatic shear-banding behavior. The equal-channel angular-pressed (ECAP) specimens consisted of
ultrafine grains and contained a considerable amount of second-phase particles, which were refined and distributed homogeneously
in the matrix as the equal-channel angular pressing pass number increased. The dynamic torsional test results indicated that
the maximum shear stress increased, while the fracture shear strain remained constant, with increasing equal-channel angular
pressing pass number. Observation of the deformed area beneath the dynamically fractured surface showed that a number of voids
initiated mainly at second-phase particle/matrix interfaces and that the number of voids increased with increasing pass number.
Adiabatic shear bands of 200 to <300 μm in width were formed in the as-extruded and 1-pass ECAP specimens having coarser particles, whereas they were hardly formed
in the four-pass and eight-pass ECAP specimens having finer particles. The possibility of adiabatic shear-band formation was
explained by concepts of absorbed deformation energy and void initiation. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|