EBSD study of superplasticity: New insight into a well-known phenomenon

Myshlyaev, М. M.; Mironov, S.; Korznikova, G. F.; Konkova, Tatyana; Korznikova, Elena A.; Aletdinov, Ainur; Khalikova, G. R.; Raab, G. I.; Semiatin, S. L.

doi:10.1016/j.jallcom.2021.162949

Cited by 19 publications

(11 citation statements)

References 72 publications

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“…This is consistent with the data published recently in [ 37 , 38 , 39 , 40 ]. It also well agrees with the recent findings reported in [ 41 ] which revealed that the formation of pronounced substructure within elongated grains can be a dominant mechanism of superplastic flow. Intensive formation of LAGBs as indicated by Figure 6 as well as by Figure 5 c as compared to Figure 5 a,b,d is thus consistent with the pronounced manifestation of SP by UFG 6060 Al alloy during tensile testing at 150 °C.…”

Section: Resultssupporting

confidence: 93%

The Microstructure and Strength of UFG 6060 Alloy after Superplastic Deformation at a Lower Homologous Temperature

et al. 2022

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The paper reports on the features of low-temperature superplasticity of the heat-treatable aluminum Al-Mg-Si alloy in the ultrafine-grained state at temperatures below 0.5 times the melting point as well as on its post-deformation microstructure and tensile strength. We show that the refined microstructure is retained after superplastic deformation in the range of deformation temperatures of 120–180 °C and strain rates of 5 × 10–3 s–1–10–4 s–1. In the absence of noticeable grain growth, the ultrafine-grained alloy maintains the strength up to 380 MPa after SP deformation, which considerably exceeds the value (250 MPa) for the alloy in the peak-aged coarse-grain state. This finding opens pathways to form high-strength articles of Al-Mg-Si alloys after superplastic forming.

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Section: Resultssupporting

confidence: 93%

The Microstructure and Strength of UFG 6060 Alloy after Superplastic Deformation at a Lower Homologous Temperature

et al. 2022

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“…The hardening of the material during its superplastic deformation can be due to active intragranular glide and/or dynamic grain growth, as evidenced by our research data and data available from other sources [1,[16][17][18][19]. Additionally, the superplastic behavior of the material is confirmed by the strain rate sensitivity measuring m ~ 0.45 for flow stresses under the temperature-rate conditions used [18,20,21] and approximating m ~ 0.5 for ideal superplasticity.…”

Section: Mechanical Behaviorsupporting

confidence: 71%

“…Any rare events of dislocation motion cannot lead to texture formation. The above observations and conclusions indicate that extensive intragranular glide occurs, as happens in other materials during superplastic deformation [15][16][17][18][19][20][21][22][23].…”

Section: Ebsd Analysis Of Microstructuresupporting

confidence: 59%

“…Therefore, this rate corresponds to the optimum temperature-rate conditions of superplasticity, which agrees with the wellknown fact that fine-grained materials, as a rule, show high-rate and/or low-temperature superplasticity. By estimates [20], the contribution of grain elongation to the total elongation of fine-grained alloy 1420 deformed under the same temperature-rate conditions can be rather high (~360% of ~1000%), and this also confirms the fact that the total strain is greatly contributed by intragranular glide.…”

Section: Discussionmentioning

confidence: 59%

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Superplastic behavior of fine-grained Al-Mg-Li alloy

et al. 2022

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The superplastic behavior of fine-grained 1420 Al-Mg-Li alloy was investigated using a modern electron microscopy technique based on automatic analysis of electron backscattered diffraction patterns (EBSD analysis). The generally accepted idea that grain boundary sliding is dominant during superplastic flow suggests the preservation of an equiaxed fine-grained structure with predominantly high-angle grain boundary misorientation in the material. The present study revealed that heating prior to the onset of deformation leads to some grain growth due to static recrystallization, and superplastic deformation is accompanied by dynamic grain growth and continuous dynamic recrystallization. Continuous recrystallization has a more significant effect on microstructural changes. This mechanism involves the transverse division of pre-elongated grains into subgrains that ultimately transform into chains of nearly equiaxed small grains, resulting in a bimodal grain structure. The data obtained, including significant strain hardening, noticeable grain elongation, the formation of a well-defined dislocation structure and subboundaries within grains, as well as the development of a pronounced crystallographic texture, provide convincing evidence of the occurrence of intragranular slip during superplastic flow throughout the entire volume of the material. A comprehensive analysis of a wide range of experimental data showed that intragranular slip plays an essential role in superplastic flow, and its contribution can be much larger than previously thought. The results obtained contribute to a better fundamental understanding of the superplasticity phenomenon.

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“…Aluminum alloys are one of the most common types of construction materials, to which various hardening methods are actively applied, including deformation [1] or thermal treatments [2], surface modification [3] and their combinations [4]. Surface modification of aluminum alloys allows one to improve chemical, physical and mechanical properties, regardless of the properties of the base material.…”

Section: Introductionmentioning

confidence: 99%

Surface hardening of an Al-Si-Cu-Ni-Mg aluminum alloy by friction stir processing and T6 heat treatment

et al. 2022

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Friction stir processing (FSP) and standard hardening T6 heat treatment were applied for local surface hardening of the АК12D aluminum (Al-12.8Si-1.67Cu-1.03Ni-0.84Mg-0.33Mn-0.23Co-0.24Fe) alloy plates obtained by hot-compression at elevated temperature. FSP was carried out by introducing a pin into the bulk of the material, followed by its movement along the surface at a traverse speed of 8 and 16 mm / min, accompanied by rotation of the pin at a speed of 2000 rpm. The effect of FSP parameters and T6 treatment on structure and hardness were investigated. It was established that FSP at 2000 rpm and 8 mm / min speed resulted in the formation of a monolithic and defect-free processing zone. The FSP and T6 treatment led to fragmentation of the primary Si and intermetallic phases and partial dissolution of intermetallic phases in the α-Al solid solution followed by decomposition and the formation of dispersed precipitates. The formation of a quasi-equiaxed finegrained structure was observed after FSP and T6 heat treatment in the stir zone. The measured Brinell hardness demonstrated an average value of 128 HB after treatment versus 103 HB in the initial state. The work reveals the features of the local surface structure refinement allowing to figure out approaches to the design of constructions with enhanced properties.

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EBSD study of superplasticity: New insight into a well-known phenomenon

Cited by 19 publications

References 72 publications

The Microstructure and Strength of UFG 6060 Alloy after Superplastic Deformation at a Lower Homologous Temperature

The Microstructure and Strength of UFG 6060 Alloy after Superplastic Deformation at a Lower Homologous Temperature

Superplastic behavior of fine-grained Al-Mg-Li alloy

Surface hardening of an Al-Si-Cu-Ni-Mg aluminum alloy by friction stir processing and T6 heat treatment

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