Structure and mechanical properties of Al–Ca alloys processed by severe plastic deformation

Рогачев, С. О.; Наумова, Е. А.; Vasileva, Ekaterina S.; Magurina, M. Yu; Сундеев, Р.В.; Велигжанин, А. А.

doi:10.1016/j.msea.2019.138410

Cited by 24 publications

(20 citation statements)

References 29 publications

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“…The problem of a simultaneous increase in strength while maintaining high plasticity during SPD is well known. There are only a few studies related to obtaining an ultrafine-grained structure in complexly alloyed aluminum alloys containing cerium and lanthanum [24,25], calcium [26] and nickel [27]. So, in work [25], for a complex eutectic alloy Al-5.4% Ce-3.1% La, a sixfold increase in strength was achieved with a twofold decrease in plasticity as a result of HPT.…”

Section: Introductionmentioning

confidence: 99%

“…So, in work [25], for a complex eutectic alloy Al-5.4% Ce-3.1% La, a sixfold increase in strength was achieved with a twofold decrease in plasticity as a result of HPT. It should be noted that in complex eutectic alloys, chemical elements can affect mutual solubility and cause other effects [26]. Therefore, the behavior of binary eutectic alloys differs significantly from the behavior of multicomponent eutectic alloys, in which there is a more complex mutual influence of the components.…”

Section: Introductionmentioning

confidence: 99%

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High Strength Al–La, Al–Ce, and Al–Ni Eutectic Aluminum Alloys Obtained by High-Pressure Torsion

et al. 2021

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A comparative analysis of the effect of high-pressure torsion (HPT) on the microstructure and tensile properties of the Al–10% La, Al–9% Ce, and Al–7% Ni model binary eutectic aluminum alloys is carried out. An HPT of 20-mm diameter specimens in as-cast state was carried out under constrained conditions, at room temperature, pressure P = 6 GPa, and number of turns N = 5. It is shown that the formation of nano- and submicrocrystalline structures and the refinement of eutectic particles in aluminum alloys simultaneously provide a multiple increase in strength while maintaining a high plasticity margin. This combination of properties has been achieved for the first time for severely deformed binary aluminum eutectics. The relationship between the type of eutectic particles, the structure formation process and the mechanical properties of the aluminum alloys has been established. The thermal stability of severely deformed aluminum alloys at heating up to 200 °C has been studied.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

High Strength Al–La, Al–Ce, and Al–Ni Eutectic Aluminum Alloys Obtained by High-Pressure Torsion

et al. 2021

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“…The Al 4 Ca phase has a tetragonal crystal lattice, so calcium is potentially a good reinforcer, which at the same time slightly reduces plasticity [3,49]. The corresponding hypothesis was tested in [53] and shown that as in binary compositions as with the addition of other elements, the Al-Ca alloys are quite malleable and capable of nanostructuring after intense plastic deformation. In the same studies, it is shown that the hardness and strength of such alloys after deformation treatment begin to decrease after heating to temperatures of 200-350 0 C. At the same time, there are structural-phase changes with a noticeable growth of grains, which reduces the potential of such alloys in the areas of high-temperature application, while increasing interest in them as high-strength materials.…”

Section: нові литі матеріалиmentioning

confidence: 99%

Analysis of Metal Systems for Developing Creep-Resistant Aluminum Alloys. A Review.

Voron¹

2021

Processy litʹâ

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This article considers the role of the main alloying elements that have the most significant impact on the formation of aluminum alloys physical and mechanical properties for operation at high temperatures. Significant interest in research and prospects of casting compositions based mainly on eutectic systems and elements or compounds that can positively affect the structure and phase composition of alloys to increase their high temperature strength is shown. The analysis and comparison of the

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“…In the Al-Ca composite before SPD, there are two phases: the fcc Al matrix and elongated submicrometer fcc Ca filaments [37]. These two phases are ductile and easily co-deform during the HPT process, which is the main difference with as-cast structures containing brittle intermetallic particles [19,[28][29][30]. During the early stage of deformation (one revolution by HPT), only a smooth hardness gradient appears (Fig.…”

Section: Influence Of Calcium On the Deformation Induced Nanoscaled Smentioning

confidence: 99%

“…However, the influence of segregations, both on electrical resistivity and mechanical strength of nanostructured Al alloys is not yet completely understood. It has already been demonstrated that grain refinement and intermetallic fragmentation can be successfully achieved by SPD processing of as-cast Al alloys containing immiscible elements (Rare Earth [28], Fe [19,29] or Ca [30]). However, starting from as-cast structures with intermetallic compounds requires huge plastic strains, and only Zener pinning can be achieved.…”

Section: -Introductionmentioning

confidence: 99%

Understanding the role of Ca segregation on thermal stability, electrical resistivity and mechanical strength of nanostructured aluminum

Sauvage

Cuvilly

Russell

et al. 2020

Materials Science and Engineering: A

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Achieving a combination of high mechanical strength and high electrical conductivity in lowweight Al alloys requires a full understanding of the relationships between nanoscaled features and physical properties. Grain boundary strengthening through grain size reduction offers some interesting possibilities but is limited by thermal stability issues. Zener pinning by stable nanoscaled particles or grain boundary segregation are well-known strategies for stabilizing grain boundaries. In this study, the Al-Ca system has been selected to investigate the way segregation affects the combination of mechanical strength and electrical resistivity. For this purpose, an Al-Ca composite material was severely deformed by high-pressure torsion to achieve a nanoscaled structure with a mean grain size of only 25 nm. X-ray diffraction, transmission electron microscopy and atom probe tomography data revealed that the fcc Ca phase was dissolved for large levels of plastic deformation leading mainly to Ca segregations along crystalline defects. The resulting microhardness of about 300 HV is much higher than predictions based on Hall and Petch Law and is attributed to limited grain boundary mediated plasticity due to Ca segregation. The electrical resistivity is also much higher than that expected for nanostructured Al. The main contribution comes from Ca segregations that lead to a fraction of electrons reflected or trapped by grain boundaries twice larger than in pure Al. The two-phase state was investigated by in-situ and ex-situ microscopy after annealing at 200°C for 30 min, where precipitation of nanoscaled Al4Ca particles occurred and the mean grain size reached 35 nm. Annealing also significantly decreased electrical resistivity, but it remained much higher than that of nanostructured pure Al, due to Al/Al4Ca interfaces that reflect or trap more than 85% of electrons.

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Structure and mechanical properties of Al–Ca alloys processed by severe plastic deformation

Cited by 24 publications

References 29 publications

High Strength Al–La, Al–Ce, and Al–Ni Eutectic Aluminum Alloys Obtained by High-Pressure Torsion

High Strength Al–La, Al–Ce, and Al–Ni Eutectic Aluminum Alloys Obtained by High-Pressure Torsion

Analysis of Metal Systems for Developing Creep-Resistant Aluminum Alloys. A Review.

Understanding the role of Ca segregation on thermal stability, electrical resistivity and mechanical strength of nanostructured aluminum

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