Failure mechanisms in superplastic AA5083 materials

Effect of Microstructure on Cavitation during Hot Deformation of a Fine-Grained Aluminum-Magnesium Alloy as Revealed through Three-Dimensional Characterization

“…[5][6][7] For SPF, grain-boundary-sliding (GBS) creep is widely recognized to be the dominant deformation mechanism in fine-grained AA5083 sheet. [5,[8][9][10][11][12][13] Under GBS creep, the dominant failure mechanism of AA5083 is cavitation.…”

“…[5,[8][9][10][11][12][13] Under GBS creep, the dominant failure mechanism of AA5083 is cavitation. [6] For QPF, solutedrag (SD) creep begins to dominate deformation as temperature decreases and strain rate increases. [5,6] Under SD creep, cavitation can still lead to failure, but flow localization (e.g., necking) becomes the controlling failure mechanism in some geometries.…”

“…[6] For QPF, solutedrag (SD) creep begins to dominate deformation as temperature decreases and strain rate increases. [5,6] Under SD creep, cavitation can still lead to failure, but flow localization (e.g., necking) becomes the controlling failure mechanism in some geometries. [6,7] Differences in cavitation evolution with strain, including cavitation growth rate and cavity morphology, have been observed between deformation controlled by GBS creep and deformation controlled by SD creep.…”

“…[5,6] Under SD creep, cavitation can still lead to failure, but flow localization (e.g., necking) becomes the controlling failure mechanism in some geometries. [6,7] Differences in cavitation evolution with strain, including cavitation growth rate and cavity morphology, have been observed between deformation controlled by GBS creep and deformation controlled by SD creep. [6] However, the initiation strains for cavitation are quite similar between GBS and SD creep deformation, [6] suggesting that cavitation initiates in a similar manner under both deformation mechanisms.…”

“…It is known from previous investigations [5,6,29] that each deformation mechanism can be produced at 450°C simply by applying different strain rates. Thus, temperature was kept constant at 450°C and strain rates were chosen, based upon prior experimental data, [5,6,29] to be 3 9 10 À4 s À1 to produce deformation dominated by GBS creep and 3 9 10 À2 s À1 to produce deformation dominated by SD creep. Previous results for the evolution of cavity area fraction with strain under each of these test conditions, [6] shown in Figure 1, served as a guide in designing experiments for this investigation.…”