Mechanical properties of single-quasicrystalline AlCuCoSi

1991 ◽  
Vol 6 (6) ◽  
pp. 1165-1168 ◽  
Author(s):  
R. Wittmann ◽  
K. Urban ◽  
M. Schandl ◽  
E. Hornbogen
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Friction Coefficient ◽  
Modulus Of Elasticity ◽  
Vickers Indentation ◽  
Indentation Method ◽  
Abrasive Friction ◽  
Highly Strained ◽  
First Time

The mechanical properties of single-quasicrystals of decagonal AlCoCuSi have been studied for the first time by applying the Vickers indentation method. The hardness has been determined as H ≃ 9.6 MPa. Estimates for the modulus of elasticity and the fracture toughness are given. The quasicrystals are highly strained internally. Scratching experiments show slight anisotropies in the abrasive friction coefficient. The dominant abrasive mechanism is microplowing.

Novel Baddeleyite-Based Zirconia Ceramics for Biomedical Applications

2017 ◽  
Vol 13 ◽  
pp. 9-14
Author(s):  
Alexander I. Tyurin ◽  
Andrey O. Zhigachev ◽  
Alexey V. Umrikhin ◽  
Vyacheslav V. Rodaev ◽  
Tatyana S. Pirozhkova
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Tetragonal Phase ◽  
Biomedical Applications ◽  
Zirconia Ceramics ◽  
Engineering Ceramics ◽  
Synthesis Conditions ◽  
Microstructure And Mechanical Properties ◽  
First Time

For the first time nanostructured engineering ceramics were prepared from natural zirconia mineral (baddeleyite) with CaO as a tetragonal phase stabilizer. The effect of synthesis conditions on microstructure and mechanical properties of the baddeleyite-based ceramics is reported, furthermore, the effect of calcia content on hardness and fracture toughness is studied. Optimal calcia concentration and synthesis conditions are found, corresponding hardness and fracture toughness values are 10,8 GPa and 13,3 MPa×m1/2. The reported mechanical properties are comparable to those typically reported for yttria-stabilized engineering zirconia ceramics, prepared from chemically synthesized zirconia.

Brittle Composites Modeling: Compazisons with MoSi2/ZrO2

1993 ◽  
Vol 322 ◽  
Author(s):  
S. P. Chen ◽  
R. Lesar ◽  
A. D. Rollett
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Transformation Toughening ◽  
Stress Changes ◽  
Simulation Results ◽  
First Time ◽  
Brittle Composites

AbstractWe have calculated the mechanical properties of brittle composites with spring-network (SN) model. The composites that we studied involve the transformation toughening effects and the accompanying micro-cracking. Our simulation results are consistent with experiments of MoSi2 toughened with ZrO2. By monitoring the stress changes due to the transformation and micro-cracking we are able to separate, for the first time, the contributions from these two competing effects. We also found that the fracture toughness of the composite increases as the modulus, interfacial cohesion of particle increases.

Processing and Properties of 2D Cf/Si-O-C Composites Using Silicone Resin

2007 ◽  
Vol 336-338 ◽  
pp. 1251-1253
Author(s):  
Ke Jian ◽  
Zhao Hui Chen ◽  
Qing Song Ma ◽  
Hai Feng Hu
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Carbon Fiber ◽  
Flexural Strength ◽  
Thermal Shock ◽  
Silicon Oxycarbide ◽  
Silicone Resin ◽  
Carbon Fiber Cloth ◽  
Thermal Shock Behavior ◽  
First Time

SR-249, a kind of polysiloxane (PSO), was used as the precursor for the first time to fabricate carbon fiber cloth reinforced silicon oxycarbide (2D Cf/Si-O-C) composites. The cure and pyrolysis of the SR-249 as well as the mechanical properties, oxidation and thermal shock behavior of the composites were investigated in the paper. The flexural strength and fracture toughness of the composites reached 217.6 MPa and 12.5 MPa·m1/2, respectively. After soaked at 1300°C under the static air for 10 min, the composites retained 58.5% flexural strength and 64.5% fracture toughness. The thermal shock behavior of the composites was studied by water quenched method. The composites retained 49.3% flexural strength and 47.4% fracture toughness after 10 times of quenching from 1200 to 20°C.

Effect of La2O3-Rich Glass Addition on Sintering of Zirconia Based Ceramics

2008 ◽  
Vol 587-588 ◽  
pp. 104-108
Author(s):  
Claudinei dos Santos ◽  
R.C. Souza ◽  
Maria Helena F.V. Fernandes ◽  
Nuno A.F. Almeida ◽  
Flávia A. Almeida ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Tetragonal Zirconia ◽  
X Ray Diffraction ◽  
Indentation Method ◽  
Glass Addition ◽  
X Ray ◽  
Heating And Cooling ◽  
Mesh Screen ◽  
Cold Pressed

In this study, the influence of La-rich glass addition and sintering conditions on the densification and mechanical properties of 3 mol.%Y2O3-stabilized tetragonal zirconia polycrystals (3Y-TZP) ceramics were evaluated. High-purity tetragonal ZrO2 powder stabilized with 3 mol.% Y2O3 and La2O3-Rich glass were used as starting powders. Two compositions, ZrO2 containing 5 and 10 wt.% of a La2O3-rich glass were studied in this work. The starting powders were mixed/milled by planetary milling, dried at 90°C for 24 hours, sieved through a 60 mesh screen and uniaxially cold pressed under 80 MPa. The samples were sintered in air at 1200, 1300 and 1400°C for 60min, and at 1450°C for 120min, with heating and cooling rates of 10°C/min. Sintered samples were characterized by relative density, X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). The mechanical properties, hardness and fracture toughness, were obtained by Vickers indentation method. Dense sintered samples were obtained for all conditions. Samples sintered at 1300°C for 60 min presented the optimal mechanical properties with hardness of 1170 kgf.mm-2 and fracture toughness of 8.3 MPam1/2.

scholarly journals Investigation of Nano-Mechanical and- Tribological Properties of Hydrogenated Diamond Like Carbon (DLC) Coatings

2016 ◽  
Vol 33 (6) ◽  
pp. 769-776 ◽  
Author(s):  
Y.-R. Jeng ◽  
S. Islam ◽  
K-T. Wu ◽  
A. Erdemir ◽  
O. Eryilmaz
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Friction Coefficient ◽  
Young’S Modulus ◽  
Tribological Properties ◽  
Young's Modulus ◽  
Chemical Vapour ◽  
Diamond Like Carbon ◽  
Dlc Coatings ◽  
Mechanical And Tribological Properties

AbstractHydrogenated diamond like Carbon (H-DLC) is a promising lubricious coating that attracted a great deal of interest in recent years mainly because of its outstanding tribological properties. In this study, the nano-mechanical and -tribological properties of a range of H-DLC films were investigated. Specifically, four kinds of H-DLC coatings were produced on Si substrates in pure acetylene, pure methane, 25% methane + 75% hydrogen, 50% methane + 50% hydrogen discharge plasmas using a plasma enhanced chemical vapour deposition (PECVD) system. Nano indentation was performed to measure the mechanical properties such as hardness and young's modulus and nanoscartching was performed to investigate the frictional behavior and wear mechanism of the H-DLC samples in open air. Moreover, Vickers indentation method was utilized to assess the fracture toughness of the samples. The results revealed that there is a strong correlation between the mechanical properties (hardness, young's modulus, fracture toughness) and the friction coefficient of DLC coatings and the source gas chemistry. Lower hydrogen to carbon ratio in source gas leads to higher hardness, young's modulus, fracture toughness and lower friction coefficient. Furthermore, lower wear volume of the coated materials was observed when the friction coefficient was lower. It was also confirmed that lower hydrogen content of the DLC coating leads to higher wear resistance under nanoscratch conditions.

Tribological Analysis of Alumina Nanocomposites for Orthopedics Applications

2008 ◽  
Author(s):  
Carlos Morillo ◽  
Yoshinori Sawae ◽  
Teruo Murakami
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Wear Rate ◽  
Fetal Bovine Serum ◽  
Wear Test ◽  
Distilled Water ◽  
Indentation Method ◽  
Hip Prostheses ◽  
Fetal Bovine ◽  
Tribological Analysis

In this study the tribological analysis of Al2O3 nanocomposites/Al2O3 pair; proposed as a candidate material to fabricate hip prostheses was carried out. Nanopowders of Al2O3 (AKP 50, 300 nm), TiO2 (PS-25, 50 nm) and Co metallic powder (Nilaco, 28 nm) were mixed and hot pressed. Wear test was carried out in a pin-on-plate tribometer, with a frequency of 1 Hz, a load of 49 N, for 4h; the counterface used was Al2O3. Mechanical properties as Vickers hardness, fracture toughness and Young’s modulus were estimated using the indentation method. Distilled water and fetal bovine serum solution (FBSS) were used as environment. It was found that the specific wear rate of Al2O3 nanocomposites was about 10−8mm3/N*m and the coefficients of friction were around 0.3–0.5 for FBSS. Worn surfaces were observed using SEM.

The Effects of MgO Addtion on the Mechanical Properties and the Phase Composition of Al2O3-TiC-TiN Ceramic Materials

2012 ◽  
Vol 457-458 ◽  
pp. 3-6
Author(s):  
Yu Huan Fei ◽  
Chuan Zhen Huang ◽  
Han Lian Liu ◽  
Bin Zou
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Phase Composition ◽  
Flexural Strength ◽  
Ceramic Materials ◽  
Bending Test ◽  
Vickers Indentation ◽  
Volume Percent ◽  
Sintered Ceramic ◽  
Three Point Bending

Al2O3-TiN-TiC ceramic materials with different MgO content were fabricated by hot-pressing technique. The MgO volume percent was varied from 0vol% to 5vol%. Three point bending test was applied to get the flexural strength and the Vickers indentation was applied to get the Vickers hardness and the fracture toughness. The phase composition of the ceramics was analyzed by XRD. The effects of the content of MgO on the mechanical properties and the phase composition of Al2O3-TiN-TiC were investigated. The results shows that the addition of MgO can change the phase composition of the sintered ceramic materials which displayed with diverse solid solutions and intermetallic compounds. The convertion of the mechanical properties can also be explained by the XRD results.

Evaluation of Fracture Toughness of Tantalum Carbide Ceramic Layer: A Vickers Indentation Method

2016 ◽  
Vol 25 (7) ◽  
pp. 3057-3064 ◽  
Author(s):  
Ke Song ◽  
Yunhua Xu ◽  
Nana Zhao ◽  
Lisheng Zhong ◽  
Zhao Shang ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Tantalum Carbide ◽  
Ceramic Layer ◽  
Vickers Indentation ◽  
Indentation Method
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