Densification mechanism of Zr-based bulk metallic glass prepared by two-step spark plasma sintering

Ding, Hao; Zhao, Zhenyu; Jin, Junsong; Deng, Lei; Gong, Pan; Wang, Xinyun

doi:10.1016/j.jallcom.2020.156724

Cited by 43 publications

(19 citation statements)

References 46 publications

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“…These large temperature differences between the top and bottom of the dies can be explained by the inhomogeneous distribution of current density for the asymmetric graphite configuration during the SPS sintering process, as illustrated in Figure 1 . Inhomogeneous distribution of the current density can also occur at the contacting points of the particles [ 46 , 47 ], leading to temperature differences inside the particles during sintering, as well.…”

Section: Resultsmentioning

confidence: 99%

Functionally Graded Al2O3–CTZ Ceramics Fabricated by Spark Plasma Sintering

et al. 2022

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We studied the fabrication of functionally graded Al2O3–CeO2-stabilized-ZrO2 (CTZ) ceramics by spark plasma sintering. The ceramic composite exhibits a gradual change in terms of composition and porosity in the axial direction. The composition gradient was created by layering starting powders with different Al2O3 to CTZ ratios, whereas the porosity gradient was established with a large temperature difference, which was induced by an asymmetric graphite tool configuration during sintering. SEM investigations confirmed the development of a porosity gradient from the top toward the bottom side of the Al2O3–CTZ ceramic and the relative pore volume distributed in a wide range from 0.02 to 100 µm for the samples sintered in asymmetric configuration (ASY), while for the reference samples (STD), the size of pores was limited in the nanometer scale. The microhardness test exhibited a gradual change along the axis of the ASY samples, reaching 10 GPa difference between the two opposite sides of the Al2O3–CTZ ceramics without any sign of delamination or cracks between the layers. The flexural strength of the samples for both series showed an increasing tendency with higher sintering temperatures. However, the ASY samples achieved higher strength due to their lower total porosity and the newly formed elongated CeAl11O18 particles.

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Section: Resultsmentioning

confidence: 99%

Functionally Graded Al2O3–CTZ Ceramics Fabricated by Spark Plasma Sintering

et al. 2022

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“…The small size of the BMG specimens synthesized by conventional casting is the most critical limitation to the exploitation of the remarkable properties of BMGs in structural applications. The restriction in sample size can be overcome by processing metallic glass powders via pressure-assisted sintering at low temperatures [27], where atomic mobility is sluggish and crystallization sets in after a much longer time compared with during the solidification of glass-forming melts, consequently giving more time for material processing. Long incubation times for crystallization is only one of the requirements for the fabrication of BMGs by PM.…”

Section: Discussionmentioning

confidence: 99%

“…The Zr 48 Cu 36 Al 8 Ag 8 powder was consolidated under argon atmosphere into cylindrical specimens (dimensions: 10 mm diameter and about 10 mm height) by uniaxial hot pressing at different temperatures (743, 753, and 758 K) using an electro-hydraulic universal axial pressing machine (WEBER PWV 30 EDS, Figure 3a,b). We used a pressure of 900 MPa, which represents the upper limit of pressure usable in our hydraulic pressing machine in the temperature range used in this work, and 10 min holding time, which is a good compromise between good densification and minimum crystallization for a series of metallic glass powders, including Ni 52.5 Nb 10 Zr 15 Ti 15 Pt 7.5 [25], Zr 70 Cu 24 Al 4 Nb 2 [26], and Zr 55 Cu 30 Ni 5 Al 10 [27]. A copper coil was used to heat the powders at a heating rate of about 40 K/min.…”

Section: Methodsmentioning

confidence: 99%

Synthesis of Bulk Zr48Cu36Al8Ag8 Metallic Glass by Hot Pressing of Amorphous Powders

Ciftci

Uhlenwinkel

et al. 2021

JMMP

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The critical cooling rate necessary for glass formation via melt solidification poses inherent constraints on sample size using conventional casting techniques. This drawback can be overcome by pressure-assisted sintering of metallic glass powders at temperatures above the glass transition, where the material shows viscous-flow behavior. Partial crystallization during sintering usually exacerbates the inherent brittleness of metallic glasses and thus needs to be avoided. In order to achieve high density of the bulk specimens while avoiding (or minimizing) crystallization, the optimal combination between low viscosity and long incubation time for crystallization must be identified. Here, by carefully selecting the time–temperature window for powder consolidation, we synthesized highly dense Zr48Cu36Ag8Al8 bulk metallic glass (BMG) with mechanical properties comparable with its cast counterpart. The larger ZrCu-based BMG specimens fabricated in this work could then be post-processed by flash-annealing, offering the possibility to fabricate monolithic metallic glasses and glass–matrix composites with enhanced room-temperature plastic deformation.

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“…Therefore, research on the fabrication of composites that include copper as a metallic filler is still ongoing. The published research results showed that adding additional metallic components such as Cr, Mo, W, or Ni prevents leakage of liquid copper during sintering [16][17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Al2O3-Cu-Ni Composites Manufactured via Uniaxial Pressing: Microstructure, Magnetic, and Mechanical Properties

et al. 2022

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This study’s main goal was to obtain and characterize Al2O3-Cu-Ni composites with different metallic phase content. The study analyzed the three series of samples differing in the metallic phase 5, 10, 15 vol.% volume contents. An identical volume share of the metallic components in the metallic phase was used. Ceramic–metal composites were formed using uniaxial pressing and sintered at a temperature of 1400 °C. The microstructural investigation of the Al2O3-Cu-Ni composite and its properties involved scanning electron microscopes observations and X-ray diffraction. The size of the metallic phase in the ceramic matrix was performed using a stereological analysis. Microhardness analysis with fracture toughness measures was applied to estimate the mechanical properties of the prepared materials. Additionally, magnetic measurements were carried out, and the saturation magnetization was determined on the obtained magnetic hysteresis loops. The prepared samples, regardless of the content of the metallic phase in each series, were characterized by a density exceeding 95% of the theoretical density. The magnetic measurements exhibited that the fabricated composites had ferromagnetic properties due to nickel and nickel-rich phases. The hardness of the samples containing 5, 10, 15 vol.% metallic phases decreased with an increase in the metallic phase content, equal to 17.60 ± 0.96 GPa, 15.40 ± 0.81 GPa, 12.6 ± 0.36 GPa, respectively.

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Densification mechanism of Zr-based bulk metallic glass prepared by two-step spark plasma sintering

Cited by 43 publications

References 46 publications

Functionally Graded Al2O3–CTZ Ceramics Fabricated by Spark Plasma Sintering

Functionally Graded Al2O3–CTZ Ceramics Fabricated by Spark Plasma Sintering

Synthesis of Bulk Zr48Cu36Al8Ag8 Metallic Glass by Hot Pressing of Amorphous Powders

Al2O3-Cu-Ni Composites Manufactured via Uniaxial Pressing: Microstructure, Magnetic, and Mechanical Properties

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