Strength and fatigue of an ultrafine-grained Al-Cu-Mg alloy

Abstract

Abstract. The dependence of strength and fatigue on microstructure of the Al-Cu-Mg alloy has been investigated. Various microstructures of the alloy were produced: the one with a coarse-grained (CG) structure after T6 heat treatment; the one with a homogeneous ultrafine-grained (UFG) structure and the one with a bimodal (mixed) structure, both processed by equal-channel angular pressing (ECAP). The mean grain size and morphology of precipitates were studied by transmission electron microscopy. The ultimate tensile strength and the fatigue endurance limit were determined using the tensile and fatigue tests of standard specimens. It is established that the formation of a homogeneous UFG structure and of a bimodal (mixed) structure alloy contributes to a significant increase in microhardness by 16% and 60%, and an increase of the ultimate tensile strength by 20 and 52%, respectively, as compared to the samples subjected to T6 heat treatment. Fatigue tests show that the alloy with a bimodal (mixed) structure has the highest fatigue endurance limit, 45% higher than in the sample subjected to T6 heat treatment. In contrast, the formation of a homogeneous UFG structure enables increasing the fatigue endurance limit by 15% only.

Effect of Process Parameters on the Microstructure and Mechanical Properties of Bars from Al-Cu-Mg Alloy Processed by Multipass Radial-Shear Rolling

“…The strength properties of the as-processed bar obtained at regime 1 UTS~430 MPa and YS~255 MPa are close to ones usually obtained for this alloy after a full cycle of heat treatment, including quenching and aging. Thus, after processing the bar obtained at regime 1 has simultaneously highest strength and ductility which are comparable to ones obtained at different SPD methods [31,32]. However, unlike the latter, RSR method used to obtain the bars can be applied in mass industrial production.…”

Effect of Hydrogen Concentration and Strain Rate on Hydrogen Embrittlement of Ultra-Fine-Grained Low-Carbon Steel

“…Grain refinement is the one of the most effective methods for strength enhancement in metals, which can be achieved without significant compromising ductility and fracture toughness [1,2]. Severe plastic deformation (SPD) techniques, among which are equal-channel angular pressing (ECAP), high-pressure torsion (HPT) and many others, have been devised to provide extreme grain size reduction down to the sub-micrometre scale in many bulk metallic materials including Al [3], Ti [4], Mg [5], Fe-based alloys [6][7][8], etc. The ultra-fine grained (UFG) materials obtained in this way demonstrate tremendous strength and ductility balance due to which they received keen attention from material scientists and engineers during the past few decades [9,10].…”