Revealing the deformation mechanisms of Cu–Al alloys with high strength and good ductility

Tian, Yanzhong; Zhao, Lijia; Park, Nokeun; Liu, R.; Zhang, P.; Zhang, Z.J.; Shibata, Akinobu; Zhang, Z.F.; Tsuji, Nobuhiro

doi:10.1016/j.actamat.2016.03.015

Cited by 121 publications

(25 citation statements)

References 44 publications

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“…10a1), which is a common feature for f.c.c. alloys with a relatively low stacking fault energy [32,33]. As deformation proceeds in the 23 µm grain-sized HEA, a Taylor lattice with parallel sets of dislocations along the glide plane is formed ( Fig.…”

Section: Resultsmentioning

confidence: 99%

The effect of carbon on the microstructures, mechanical properties, and deformation mechanisms of thermo-mechanically treated Fe40.4Ni11.3Mn34.8Al7.5Cr6 high entropy alloys

et al. 2017

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The effects of cold rolling followed by annealing on the mechanical properties and dislocation substructure evolution of undoped and 1.1 at. % carbon-doped Fe 40.4 Ni 11.3 Mn 34.8 Al 7.5 Cr 6 high entropy alloys (HEAs) have been investigated. X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atom probe tomography (APT) were employed to characterize the microstructures. The as-cast HEAs were coarse-grained and single phase f.c.c., whereas the thermo-mechanical treatment caused recrystallization (to fine grain sizes) and precipitation (a B2 phase for the undoped HEA; and a B2 phase, and M 23 C 6 and M 7 C 3 carbides for the C-doped HEA). Carbon, which was found to have segregated to the grain boundaries using APT, retarded recrystallization. The reduction in grain size resulted in a sharp increase in strength, while the precipitation, which produced only a small increase in strength, probably accounted for the small decrease in ductility for both undoped and C-doped HEAs. For both undoped and C-doped HEAs, the smaller grain-sized material initially exhibited higher strain hardening than the coarse-grained material but showed a 3 much lower strain hardening at large tensile strains. Wavy slip in the undoped HEAs and planar slip in C-doped HEAs were found at the early stages of deformation irrespective of grain size. At higher strains, dislocation cell structures formed in the 19 µm grain-sized undoped HEA, while microbands formed in the 23 µm grain-sized C-doped HEA. In contrast, localized dislocation clusters were found in both HEAs at the finest grain sizes (5 µm). The inhibition of grain subdivision by the grain boundaries and precipitates lead to the transformation from regular dislocation configurations consisting of dislocationcells and microbands to irregular dislocation configurations consisting of localized dislocation clusters, which further account for the decrease in ductility. Investigation of the formation mechanism and strain hardening of dislocation cells and microbands could benefit future structural material design.

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Section: Resultsmentioning

confidence: 99%

The effect of carbon on the microstructures, mechanical properties, and deformation mechanisms of thermo-mechanically treated Fe40.4Ni11.3Mn34.8Al7.5Cr6 high entropy alloys

et al. 2017

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“…At a given grain size, it is interesting to find that the UTS can be enhanced monotonically with decreasing SFE, as shown in Figure 1(d), which agrees well with previous reports. [15,22,27] In contrast, monotonic enhancement of the UE was not obtained, as shown in Figure 1(e), where four conclusions can be generally obtained. Firstly, the UE has a linear relationship with the inverse square root of grain size (HallPetch type) for each alloy, and the equations can be described as …”

mentioning

confidence: 75%

“…[18] When the grain size is further increased to 1.5 and 3 μm, it is found that the strain-hardening rates especially at the later tensile process are comparable between the Cu-11Al and Cu-15Al alloys, as shown in Figure 3(b) and 3(c), which may be related to the dominating deformation modes of SFs and DTs. [18,27] It is observed that the flow stress of the Cu-15Al alloy is much higher than the Cu-11Al alloy as shown in Figure 3(a)-(c), thus resulting in a lower ductility in the Cu-15Al alloy though comparable strain-hardening rate is achieved. For the Cu-11Al alloy with a medium SFE, the high strain-hardening rate and medium flow stress collectively harvest the highest ductility among the three Cu-Al alloys.…”

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confidence: 91%

“…[29] In addition, the strain-hardening curves keep stable with increasing the grain size, and the strain-hardening rate is always much smaller than the Cu-11Al alloy as shown in Figure 3(a)-(c), inducing a lower elongation in the Cu-4Al alloy than the Cu-11Al alloy. [27] Secondly, the tensile deformation behavior will be compared between the Cu-11Al alloy and Cu15Al alloy. The strain-hardening rate of the Cu-15Al alloy is slightly lower than the Cu-11Al alloy when the grain size is about 0.6 μm, as shown in Figure 3(a), and the plastic deformation is largely undertaken by SFs and DTs since only few dislocations were detected in the Cu15Al alloy.…”

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confidence: 99%

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Ductility Sensitivity to Stacking Fault Energy and Grain Size in Cu–Al Alloys

Tian

Shibata

Zhang

et al. 2016

Materials Research Letters

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“…Overall, the three MEAs all possess excellent strain-hardening capability. While the Cr30Co30Ni40 and CrCoNi MEA share the same strain-hardening curve, the Cr36Co36Ni28 MEA with the lowest SFE shows higher strain-hardening rate when the true strain is smaller than 0.065, which can be induced by the early onset of profuse SFs acting as strong barriers for dislocation glide [80,81]. One more note to add is that the strain-hardening abilities caused by the mechanisms of → DIMT and DT (as evidenced in the following) are very similar in these MEAs, which calls for future studies to understand in detail that how dislocations interact with twin and fcc/hcp phase boundaries and their impact on the strain-hardening abilities.…”

Section: Experimental Verification Of Alloy Designmentioning

confidence: 96%

Designing Transformation-Induced Plasticity and Twinning-Induced Plasticity Cr-Co-Ni Medium Entropy Alloys: Theory and Experiment

Yang

Tian

et al. 2020

SSRN Journal

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In order to efficiently explore the nearly infinite composition space in multicomponent solid solution alloys, it is important to establish predictive design strategies and use computation-aided methods. In the present work, we demonstrated the density functional theory calculations informed design routes for realizing transformation-induced plasticity (TRIP) and twinning-induced plasticity (TWIP) in Cr-Co-Ni medium entropy alloys (MEAs). We systematically studied the effects of magnetism and chemical composition on the generalized stacking fault energy surface (-surface) and showed that both chemistry and the coupled magnetic state strongly affect the -surface, consequently, the primary deformation modes. Based on the calculated effective energy barriers for the competing deformation modes, we constructed composition and magnetism dependent deformation maps at both room and cryogenic temperatures. Accordingly, we proposed various design routes for achieving desired primary deformation modes in the ternary Cr-Co-Ni alloys. The deformation mechanisms predicted by our theoretical models are in nice agreement with available experimental observations in literature. Furthermore, we fabricated two non-equiatomic Cr-Co-Ni MEAs possessing the designed TWIP and TRIP effects, showing excellent combinations of tensile strength and ductility. Corresponding authors: a Song Lu, songlu@kth.se b Yanzhong Tian,

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Revealing the deformation mechanisms of Cu–Al alloys with high strength and good ductility

Cited by 121 publications

References 44 publications

The effect of carbon on the microstructures, mechanical properties, and deformation mechanisms of thermo-mechanically treated Fe40.4Ni11.3Mn34.8Al7.5Cr6 high entropy alloys

The effect of carbon on the microstructures, mechanical properties, and deformation mechanisms of thermo-mechanically treated Fe40.4Ni11.3Mn34.8Al7.5Cr6 high entropy alloys

Ductility Sensitivity to Stacking Fault Energy and Grain Size in Cu–Al Alloys

Designing Transformation-Induced Plasticity and Twinning-Induced Plasticity Cr-Co-Ni Medium Entropy Alloys: Theory and Experiment

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