Formation and control of “intragranular” ZrO2 strengthened and toughened Al2O3 ceramics

Du, Wenya; Ai, Yongfeng; He, Wen; Liang, Bingliang; Lv, Chen

doi:10.1016/j.ceramint.2019.12.080

Cited by 56 publications

(14 citation statements)

References 30 publications

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“…Consequently, in addition to the microstructure (porosity), the composition of the samples has obvious effects on the ultimate compressive strength of the samples. According to the reported studies [ 45 , 46 ], the intragranular ZrO 2 effectively improves the strength of the composite, due to intragranular ZrO 2 creating sub-grain boundaries in the Al 2 O 3 particles; therefore, achieving refinement of the strengthening structure.…”

Section: Resultsmentioning

confidence: 99%

Preparation and Characterization of Fibrous Alumina and Zirconia Toughened Alumina Ceramics with Gradient Porosity

et al. 2022

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This paper investigated a synthesis process for highly porous Al2O3, Y-ZTA, and Ce-ZTA ceramic nanocomposites with gradient microstructure and improved mechanical properties. Ceramic nanofibres were synthesized as the starting material. The gradient microstructure was developed during spark plasma sintering using an asymmetric graphite arrangement that generated significant temperature differences (80–100 °C) between the opposite sides of the samples. Structural and mechanical properties of the fibrous ceramic composites were investigated. The effect of the temperature gradient on properties was also discussed. While the asymmetric configuration resulted in a gradient porosity, reference samples fabricated in standard graphite configuration were uniformly porous. The gradient structure and the ZrO2 addition led to improved hardness and compression strength of the sintered samples. However, the opposite sides of the samples exhibited considerable variations in both microstructure and in terms of properties. The upper part of the Ce-ZTA ceramic showed a highly porous structure with 18.2 GPa hardness, while the opposite side was highly densified with 23.0 GPa hardness. Compressive strength was 46.1 MPa and 52.1 MPa for Y-ZTA and Ce-ZTA sintered at 1300 °C, respectively, despite their high porosity. The research provided a promising approach to prepare highly porous ZTA composites with high strength for a wide range of applications.

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Section: Resultsmentioning

confidence: 99%

Preparation and Characterization of Fibrous Alumina and Zirconia Toughened Alumina Ceramics with Gradient Porosity

et al. 2022

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“…These strain fields improve the strength of a composite by restricting dislocation movement and increasing deformation resistance. 34,37 As seen in Figure 2, ZrTiO 4 crystallizes in the orthorhombic phase, whereas Al 2 O 3 crystallizes in the hexagonal phase.…”

Section: Resultsmentioning

confidence: 99%

“…The strain field formed due to coherent distortion between matrixes of the second phase particles when the lattice constant of the ZrTiO 4 phase is different from the alumina matrix. These strain fields improve the strength of a composite by restricting dislocation movement and increasing deformation resistance 34,37 . As seen in Figure 2, ZrTiO 4 crystallizes in the orthorhombic phase, whereas Al 2 O 3 crystallizes in the hexagonal phase.…”

Section: Resultsmentioning

confidence: 99%

“…The presence of an "intragranular" structure (the matrix contains second phase particles) can improve mechanical properties. 34 Sintering procedures for creating "intragranular" structures in ceramic composites and the addition of dispersion to the ceramic composite are becoming increasingly significant. 35,36 Adding TiO 2 in CSZTA formed intragranular structures, increasing the composite's strength and toughness.…”

Section: Introductionmentioning

confidence: 99%

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Effect of two‐step sintering on microstructure and mechanical properties of ceria‐stabilized zirconia‐toughened alumina‐added titania (CSZTA–TiO₂)

Eggidi

Pandey

2022

Int J Applied Ceramic Tech

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Effect of two‐step sintering (TSS) on microstructure and mechanical properties of ceria‐stabilized zirconia‐toughened alumina with added TiO2 (CSZTA–TiO2) was studied. A coprecipitation technique was used to produce the CSZTA–TiO2 powders. The synthesized powders were compacted using a uniaxial hydraulic press and conventionally sintered in air. The phase and microstructure of sintered samples were studied using X‐ray diffraction and scanning electron microscopy techniques. Phases were quantified using the Rietveld refinement method. Different TSS schedules were followed to optimize microstructure and mechanical properties. Mechanical properties of the CSZTA‐4TiO2 composite were evaluated and found as follows: Vickers's hardness of 1650 ± 9.6 HV10, indentation fracture toughness of 8.45 ± .14 MPa √m, compressive strength of 2088 MPa, and Young's modulus of 158 GPa.

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“…This ceramic is commonly reinforced with a second phase, such as yttria-tetragonal zirconia polycrystals (Y-TZP), aiming to improve mechanical properties at room temperature. However, its low hardness associated with hydrothermal degradation and a transformation of phases at 1170 °C limit its use in certain applications [3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Dry machining of nodular cast iron using a YAG-reinforced alumina ceramic cutting tool

Sousa¹,

Simba²,

Souza

et al. 2022

Preprint

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In this work an alumina-yttrium aluminum garnet (Al2O3-YAG) cutting tool was developed and characterized aiming application in dry machining of nodular (spheroidal) cast iron. Ceramic powders containing 85 wt.% Al2O3 and 15 wt.% Y3Al5O12(YAG) were homogenized, compacted, and sintered at 1600 ºC for 2h at a heating rate of 5 °C/min. The sintered ceramic presented relative density of 98.3 ±0.2%. X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) revealed α-Al2O3 and YAG as crystal phases, both with equiaxed grains with average sizes of 1-4 𝜇m (Al2O3 phase) and 0.7-1 𝜇m (YAG phase). In addition, this ceramic composite presented Vickers hardness and fracture toughness of 15.2 ±0.2 GPa and 4.6 ±0.3 MPa.m1/2, respectively. The dry machining performance of the Al2O3-YAG cutting tool was compared with that of a commercial cemented carbide cutting tool using cutting speed (VC) of 200 and 500 m/min, feed rate (f) of 0.25 and 0.10 mm/rev, and axial depth of cut (ap) of 0.60 mm. The results showed that the best setting for the cemented carbide cutting tool was obtained at VC=200 m/min and f=0.25 mm/rev, which produced the best machinability with average surface roughness (Ra) of 3.516 μm, cutting length (LC) of 6000 m, and maximum flank wear (VBmax) of 0.58 mm. For the Al2O3-YAG cutting tool, the best setting was achieved at VC=500 m/min and f=0.10 mm/rev, which produced Ra=0.848 μm, LC=12,293 m, and VBmax=0.54 mm.

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Formation and control of “intragranular” ZrO2 strengthened and toughened Al2O3 ceramics

Cited by 56 publications

References 30 publications

Preparation and Characterization of Fibrous Alumina and Zirconia Toughened Alumina Ceramics with Gradient Porosity

Preparation and Characterization of Fibrous Alumina and Zirconia Toughened Alumina Ceramics with Gradient Porosity

Effect of two‐step sintering on microstructure and mechanical properties of ceria‐stabilized zirconia‐toughened alumina‐added titania (CSZTA–TiO₂)

Dry machining of nodular cast iron using a YAG-reinforced alumina ceramic cutting tool

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Formation and control of “intragranular” ZrO2 strengthened and toughened Al2O3 ceramics

Cited by 56 publications

References 30 publications

Preparation and Characterization of Fibrous Alumina and Zirconia Toughened Alumina Ceramics with Gradient Porosity

Preparation and Characterization of Fibrous Alumina and Zirconia Toughened Alumina Ceramics with Gradient Porosity

Effect of two‐step sintering on microstructure and mechanical properties of ceria‐stabilized zirconia‐toughened alumina‐added titania (CSZTA–TiO2)

Dry machining of nodular cast iron using a YAG-reinforced alumina ceramic cutting tool

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Effect of two‐step sintering on microstructure and mechanical properties of ceria‐stabilized zirconia‐toughened alumina‐added titania (CSZTA–TiO₂)