Effect of Various SPD Techniques on Structure and Superplastic Deformation of Two Phase MgLiAl Alloy

Bobrowski, Piotr; Rusz, Stanislav; Hilšer, Ondřej; Tański, Tomasz; Borek, Wojciech; Łagoda, М.; Ostachowski, Paweł; Pałka, P.; Boczkal, G.; Kuc, D.; Mikuszewski, T.

doi:10.1007/s12540-018-0118-3

Cited by 16 publications

(20 citation statements)

References 16 publications

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“…3. The presence of such fine hcp α particles was earlier reported in deformed β phase Mg-Li alloys [28] or dual phase Mg-Li alloys after ECAP or multiple forging SPD [32,35]. It is important to note that the morphologies of KOBO processed α and β phases are slightly different.…”

Section: Methodsmentioning

confidence: 52%

“…In the KOBO technique, a combination of an extrusion process with additional plastic deformation by reversible torsion of the die allows a very high deformation at room temperature. In the case of ternary Mg-Li-Al alloy, high grain refinement, for α phase below 1 μm and for β phase down to 2.5 μm, were obtained by this technique [32]. High grain refinements in the range 4-7 μm for the AZ31 alloy [33] and below 1 μm in the case of WE43 [34] alloy were also achieved with this technique.…”

Section: Introductionmentioning

confidence: 78%

“…The deformation was performed by extrusion with reversibly rotating die at room temperature to avoid dynamic grain growth assuming that scandium increases the recrystallization temperature and improves the grain refinement as observed in [21][22][23]. Following the KOBO extrusion, the bars were again deformed by multidirectional forging using Maxstrain Gleeble equipment as described in [32]. It allowed the performance of cyclic forging in two perpendicular directions at the temperatures of 150 °C and 200 °C in the way shown in the scheme in Fig.…”

Section: Methodsmentioning

confidence: 99%

“…The SADP from the dark area shows rather a complicated pattern that can be solved as a mixture of the bcc β phase of [001] zone axis orientation, the hcp α phase of [011 0] zone axis orientation and intermetallic phases formed due to the aluminum and scandium additions that were indexed as Al 3 Sc of [001] zone axis and LiMgAl 2 with the [014] zone axis. Comparing the microstructures of hcp α and bcc β phases, much more precipitates within the β phase were recorded due to higher Li and 1% Al [28] and in the dual phase Mg-Li-Al alloys after the ECAP or multiple forging SPD [25,32,35]. The origin of this phase is not well understood, however it may be possible that during severe plastic deformation, diffusion assisted α phase formation was initiated on frequent crystal defects within the β phase which as softer one carries most of sample deformation during either ECAP or KOBO processing and consequently the α phase particles form in the whole volume of β grains.…”

Section: Methodsmentioning

confidence: 99%

“…Equal Channel Angular Pressing (ECAP) has been the most popular mode of SPD leading to grain refinement in the range of 200 nm of the β phase [28] up to a few μm [13,[29][30][31]. Finer grains in the range of a few hundred nm can be obtained using either High Pressure Torsion (HPT) [11,20,24] and multidirectional forging [7,16,32].…”

Section: Introductionmentioning

confidence: 99%

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Effect of KOBO Extrusion and Following Cyclic Forging on Grain Refinement of Mg–9Li–2Al–0.5Sc Alloy

et al. 2019

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KOBO type extrusion and following cyclic forging in two perpendicular directions at temperatures 150-200 °C were applied to new Mg-9Li-2Al-0.5Sc alloy to study its effect on strength and microstructure evolution. KOBO extrusion of as cast ingot caused significant grain refinement of (α + β) dual phase Mg-9Li-2Al-0.5Sc alloys down to range 1-10 μm for hcp α phase and 1-5 μm for the β phase as resulted from EBSD studies. At that stage ultimate tensile strength UTS of 168 MPa and elongation of 36% were attained. Additional deformation by cyclic forging alternatively from 2 perpendicular directions caused formation of much finer grains of average size of few hundred nm observed using TEM and close to 1 μm applying EBSD technique. Tensile strength increased after that operation above 200 MPa and elongation above 40%, which were the highest observed in the dual phase Mg-Li based alloys. Deformation by cyclic forging induced formation of strong texture with 0001 plane parallel to forging directions. Additional precipitates of size below 1 μm at α/β interfaces or within β phase were identified as hcp AlSc 2 phase. Fine particles of hcp α phase were observed after severe plastic deformation SPD within β phase grains, as effect of diffusion assisted deformation. The amount of hcp α phase increased after SPD up to 70% from initial 40%. High density of defects at α/β interfaces on 0001 planes observed in HRTEM mode was responsible for promotion of hcp phase formation during SPD.

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Section: Methodsmentioning

confidence: 52%

Section: Introductionmentioning

confidence: 78%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Effect of KOBO Extrusion and Following Cyclic Forging on Grain Refinement of Mg–9Li–2Al–0.5Sc Alloy

et al. 2019

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Microstructure, wettability and strength of cryo‐deformed tin‐3.0 silver‐0.5 copper solder

Sharif

Koay

2021

Materialwissenschaft Werkst

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This project aims to assess the influence of cryogenic treatment prior to passing the solder sample through an equal channel angular pressing die in order to refine the microstructure of solder and thus, gain improvement of mechanical properties of solder joint. In this work, commercial tin-3.0silver-0.5copper solder alloy was subjected to severe plastic deformation by passing through the die for 1 pass, and prior to this, dipped in nitrogen for 10 minutes, 20 minutes and 30 minutes. Hardness and wettability of solder reflowed on bare copper substrate were measured along with strength of solder joint via lap joint shear strength test. Cryo-deformed solder was found to have higher hardness, and wettability had also improved along with the strength of solder joint. Improvement could be due to grain refinement as observed in microstructure and also the more uniform distribution of eutectic network. Dipping for 10 minutes gave the best improvement, whereas longer dipping (20 and 30 minutes) seems to have deteriorating effect to the wettability and mechanical properties. Cryo-deformation showed significant improvement on the wettability and mechanical properties of solder, and could potentially lead to higher reliability of solder joint.

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Superplastic deformation of Mg–9Li–2Al–0.5Sc alloy after grain refinement by KoBo extrusion and cyclic forging

Kalita

Maziarz

Faryna

2020

Archiv.Civ.Mech.Eng

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The quaternary Mg–9Li–2Al–0.5Sc alloy (in wt%) was prepared from pure components. After homogenization, the alloy was subjected to severe plastic deformation by KoBo extrusion and cyclic forging leading to grain refinement in the range of 0.5–2 µm of hexagonal close-packed (HCP) α phase. Deformed alloys showed high ultimate tensile strength near 200 MPa and good elongation in the range 30–40% at room temperature (RT). Large elongations close to 200% were obtained during the tensile test at a temperature of 200 °C. Deformed samples showed the presence of multiple voids confirming grain boundary sliding mechanism of deformation. Twins on {10$$\overline{1}$$ 1 ¯ 2} planes were identified using electron backscatter diffraction analysis, being in a good agreement with the earlier observation of Mg–Li and Mg–Sc alloys. Intermetallic phases such as cubic MgSc were identified in deformed alloys mostly within HCP α phase, whereas HCP MgSc2 particles were observed within body-centered cubic (BCC) β phase. Intermetallic phases were responsible for RT strengthening of alloys and slightly lower tensile elongation during superplastic deformation. Formation of the HCP α phase was observed within the BCC β phase in tensile deformed alloys. Atomic-level nucleation of HCP phase within the β phase was identified by the use of high-resolution transmission electron microscopy technique.

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Effect of Various SPD Techniques on Structure and Superplastic Deformation of Two Phase MgLiAl Alloy

Cited by 16 publications

References 16 publications

Effect of KOBO Extrusion and Following Cyclic Forging on Grain Refinement of Mg–9Li–2Al–0.5Sc Alloy

Effect of KOBO Extrusion and Following Cyclic Forging on Grain Refinement of Mg–9Li–2Al–0.5Sc Alloy

Microstructure, wettability and strength of cryo‐deformed tin‐3.0 silver‐0.5 copper solder

Superplastic deformation of Mg–9Li–2Al–0.5Sc alloy after grain refinement by KoBo extrusion and cyclic forging

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