scholarly journals Effect of Multiwalled Carbon Nanotubes on Improvement of Fracture Toughness of Spark-Plasma-Sintered Yttria-Stabilized Zirconia Nanocomposites

2021 ◽  
Author(s):  
T. Arunkumar ◽  
G. Anand ◽  
Ram Subbiah ◽  
R. Karthikeyan ◽  
Jaya Jeevahan
Keyword(s):  
Carbon Nanotubes ◽  
Fracture Toughness ◽  
Wear Resistance ◽  
Weight Ratio ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
Multiwalled Carbon ◽  
Single Beam ◽  
Pull Out ◽  
Spark Plasma

AbstractHighly dense yttria-stabilized zirconia (YSZ) nano-ceramics reinforced with TC-CVD-synthesized multiwall carbon nanotubes (MWCNTs) were fabricated using spark plasma sintering at a temperature of 1350°C, the heating rate of 100 °C/min and pressure of 50MPa with a dwell time of 10 minutes. The identical parameters were utilized for fabricating composites with a varying weight ratio of YSZ and MWNCTs. The samples were characterized for their phase transformation, microstructure and elemental composition using x-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). The physical and mechanical properties such as density, porosity, hardness, fracture toughness and wear were also investigated. The increase in the MWCNTs concentration has resulted in the deterioration of the hardness due to CNT agglomerations. The wear resistance of the composites revealed MWNCTs enhanced wear resistance of YSZ nanocomposite by undergoing MWNCTs pull-out and crack branching mechanisms. Further indentation method and single-beam V-notch beam (SEVNB) methods were utilized to study the effect of MWCNTs on the fracture toughness of the nanocomposites. The fracture toughness of YC1 (6.58 ± 0.3 MPa m1/2) was 21% higher than the YSZ (5.21 ± 0.2 MPa m1/2) due to the toughening mechanisms attributable to crack deflection, branching and bridging of MWCNTs.

Effect of MWCNTs on Improvement of Fracture Toughness of Spark Plasma Sintered SiC Nano-Composites

2020 ◽  
Vol 16 ◽  
Author(s):  
T. Arunkumar ◽  
R. Karthikeyan ◽  
R. Ram Subramani ◽  
M. Anish ◽  
J. Theerthagiri ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Silicon Carbide ◽  
Particle Size ◽  
Weight Ratio ◽  
External Pressure ◽  
Ductile Material ◽  
Multiwalled Carbon ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Temperature Rate

Background: Silicon carbide (SiC) ceramics are promising engineering material due to its phenomenal properties, such as strong corrosion resistance, high-temperature hardness, wear resistance, high thermal conductivity and high stability in aggressive environment. The key problem of SiC is low fracture toughness due to its brittle nature and to circumvent this, herein high ductile material like MWCNT was used as reinforcement by different proportions. Methods: Nanocrystalline powdered Silicon Carbide (SiC) of particle size of 40 nm and x % weight ratio of SiC (x = 95%, 90% and 85%) + y % weight ratio of multiwalled carbon nanotubes (MWCNTs) of particle size of 20 nm (y= 5%, 10% and 15%) composites were ball milled and fabricated using spark plasma sintering process with temperature rate of 100 oC/min and external pressure of 50 MPa. The sintered samples were tested according to ASTM standards to verify the mechanical properties of the samples. Further, lattice strain, crystalline size was determined by XRD and crack bridging mechanism was studied by FESEM. Results: It was observed that the uniform distributions of MWCNTs were achieved through ultrasonification and ball milling processes, which play a predominant role in increasing fracture toughness. The fracture toughness of the composite improves drastically from 3.71 MPa m1/2 (100% SiC) to 10.21 MPa m1/2 (85% SiC-15% MWCNT). The theoretical and relative densities of the materials were gradually reduced due to the increase in MWCNTs which is due to lower density of the reinforcement material and increase in porosity of the samples. Conclusion: The MWCNTs act as a bridging aid in sintered samples, FESEM image signifies some pull-outs and crack branching mechanism of MWCNTs which is the reason for increase in the fracture toughness of SiC.

Dispersion of Carbon Nanotubes in Alumina Using a Novel Mixing Technique and Spark Plasma Sintering of the Nanocomposites with Improved Fracture Toughness

2014 ◽  
Vol 89 ◽  
pp. 76-81 ◽  
Author(s):  
Nabi Bakhsh ◽  
Fazal Ahmad Khalid ◽  
Abbas Saeed Hakeem ◽  
Tahar Laoui
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Fracture Toughness ◽  
Spark Plasma Sintering ◽  
Alumina Powder ◽  
Alumina Matrix ◽  
Pull Out ◽  
Plasma Sintering ◽  
Structural Applications ◽  
Spark Plasma

The present study emphasizes on the fabrication of carbon nanotubes (CNTs) reinforced alumina nanocomposites for structural applications. A new technique for the mixing and dispersion of CNTs in alumina powder was employed. Spark plasma sintering (SPS) technique was used for the fabrication of nanocomposites with varying amounts of as-received CNTs (1, 2 and 3 weight %) in alumina matrix. Densification behavior, hardness and fracture toughness of the nanocomposites were studied. A comparison of mechanical properties of the desired nanocomposites was presented. An improvement in fracture toughness of approximately 14% at 1 wt% CNT-alumina nanocomposite over monolithic alumina compacts was observed due to better dispersion of CNTs in alumina matrix that ultimately helped in grain growth suppression to provide finer grain in the nanocomposites. The fractured surfaces also revealed the presence of CNTs bridging and pull out that aided in the improvement of mechanical properties. The synthesized samples were characterized using field emission scanning electron microscopy, X-ray diffraction, Raman spectroscopy, densification, Vickers hardness testing and fracture toughness measurements.

The effects of multiwalled carbon nanotubes on the hot-pressed 3mol% yttria stabilized zirconia ceramics

2009 ◽  
Vol 520 (1-2) ◽  
pp. 153-157 ◽  
Author(s):  
Ji Ping Zhou ◽  
Qian Ming Gong ◽  
Ke Yi Yuan ◽  
Jian Jun Wu ◽  
Yi fang Chen ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
Zirconia Ceramics ◽  
Multiwalled Carbon

Improved fracture toughness of immiscible polypropylene/ethylene-co-vinyl acetate blends with multiwalled carbon nanotubes

Polymer ◽  
2009 ◽  
Vol 50 (14) ◽  
pp. 3072-3078 ◽  
Author(s):  
Li Liu ◽  
Yong Wang ◽  
Yanli Li ◽  
Jun Wu ◽  
Zuowan Zhou ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Fracture Toughness ◽  
Multiwalled Carbon Nanotubes ◽  
Vinyl Acetate ◽  
Multiwalled Carbon

scholarly journals Effect of Crack Bridging on the Toughening of Ceramic/Graphene Composites

2018 ◽  
Vol 57 (1) ◽  
pp. 54-62 ◽  
Author(s):  
S.V. Bobylev ◽  
A.G. Sheinerman
Keyword(s):  
Experimental Data ◽  
Fracture Toughness ◽  
Crack Growth ◽  
Crack Deflection ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
Crack Bridging ◽  
The Matrix ◽  
Graphene Content ◽  
Graphene Platelets

Abstract A model is proposed describing the effect of crack bridging on the fracture toughness of ceramic/graphene composites. The dependences of the fracture toughness on the graphene content and the sizes of the graphene platelets are calculated in the exemplary case of yttria stabilized zirconia (YSZ)/graphene composites. The calculations predict that if crack bridging prevails over crack deflection during crack growth, the maximum toughening can be achieved in the case of long graphene platelets provided that the latter do not rupture and adhere well to the matrix. The model shows good correlation with the experimental data at low graphene concentrations.

Mechanical and Structural Properties of Ion Implanted Yttria Stabiizeed Zirconia Ceramics

1983 ◽  
Vol 24 ◽  
Author(s):  
J. K. Cochran ◽  
K. O. Legg ◽  
H. F. Solnick-Legg
Keyword(s):  
Fracture Toughness ◽  
Penetration Depth ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
Zirconia Ceramics ◽  
Mechanical And Structural Properties ◽  
Knoop Microhardness ◽  
Vicker’S Microhardness ◽  
Reflection Electron Diffraction ◽  
Indenter Penetration

ABSTRACTSingle crystal yttria stabilized zirconia was implanted with 100 keV Ca+, Al+, and O2+ ions at fluences of 1015 to 6 × 1016 ions/cm2; . Blistering was observed at doses of 3 × 1016; O2;+ cm−2; and 6 × 1016; Al+ cm−2; but none was evident with Ca+. Knoop microhardness with a shallow indenter penetration depth peaked at a dose of 1016; ions/cm−2; for both Al+ and O2;+ but Ca+ produced no effect on microhardness. Vicker's microhardness with a much greater indenter penetration depth was not changed detectably by implantation but fracture toughness measurements from the same Vicker's indentations exhibited 10–23% increases at the highest O2+ doses and 20–25% increases at high Al+ doses. Annealing the highest implant doses at 1200° reduced the fracture toughness to pre-implant levels. Reflection electron diffraction showed that the surface had not been made amorphous by the 6 × 1016; Al+ dose as a well crystallized diffraction pattern was obtained.

Environmental Effect on the Crack Behavior of Yttria-Stabilized Zirconia During Laser Drilling

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Hong Shen ◽  
Juan Jiang ◽  
Decai Feng ◽  
Chen Xing ◽  
Xiaofeng Zhao ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Phase Transformation ◽  
Environmental Effect ◽  
Monoclinic Phase ◽  
Oxygen Vacancies ◽  
High Stress ◽  
Laser Drilling ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
Crack Behavior

The crack behaviors of yttrium-stabilized zirconia during laser drilling in air, vacuum, and water environments were investigated. Due to the high stress and low fracture toughness induced by tetragonal-monoclinic phase transformation, tremendous cracks occur during drilling in air. Contrastly, cracks were reduced in vacuum drilling since the phase transformation was suppressed due to the generation of oxygen vacancies. By protection of water, no cracks were observed due to low stress and maintained fracture toughness. The crack mechanisms in different drilling media were discussed.

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