Dynamic deformation and fracture behavior of ultrafine-grained aluminum alloy fabricates by equal-channel angular pressing

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 Ͻ300 m 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.

Microstructure and mechanical properties of the start bending point for X90 bend

“…Some fine rod-shaped M/A constituents are observed to be distributed on the bainitic lath boundaries (Figure 4(a)). It is generally believed that there are some substructures in the QPF and AF during the rolling process of the TMCP because of shear transformation [36]. After hot induction bending, some dislocation cells are eliminated, and the laths widen and deteriorate.…”

Modeling of continuous dynamic recrystallization in commercial-purity aluminum

“…The data is compiled from various sources. ε vp eff AA1200 [35] Al 5N [28] 5083 Al [36] Al3Mg [37] AA1050 [38] 0 41 .48 280 200 250 100 1 3.83 120 0.55 --2 2.82 82 ---3 2.22 77 ---4 2…”