scholarly journals The Fabrication and Mechanical Properties of Laminated ZrB2-Mo5SiB2 Ceramics with an Mo-Mo5SiB2 Interlayer

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2018
Author(s):  
Yanfang Wang ◽  
Mingliang Li ◽  
Hailong Wang ◽  
Gang Shao ◽  
Jinpeng Zhu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Residual Stress ◽  
High Temperature ◽  
Flexural Strength ◽  
Layer Thickness ◽  
Thickness Ratio ◽  
High Fracture Toughness ◽  
High Fracture ◽  
Layer Thickness Ratio

The excellent physical and chemical properties of ultra-high temperature ceramics make them suitable for many high-temperature structural components, while their poor toughness and high sintering temperature become key limitations to their application. Laminated toughening has long been considered an effective toughening method to improve the mechanical properties of ceramics. In this study, laminated ZrB2-Mo5SiB2 ceramics with an Mo-Mo5SiB2 interlayer were fabricated by tape casting and hot press sintering at 1900 °C for 2 h. Different layer thickness ratios between the matrix layer and the interlayer were designed to illustrate the toughening mechanism. Both the fracture toughness and flexural strength of the laminated ceramics showed a trend of first increasing and then decreasing with the increase of the layer thickness ratio. High fracture toughness (9.89 ± 0.26 MPa·m1/2) and flexural strength (431.6 ± 15.1 MPa) were obtained when the layer thickness ratio was 13. The improvement in fracture toughness of the laminated ceramics could be attributed to the generation of the residual stress, the deflection and the bifurcation of the cracks. Residual stress that developed in the laminated ceramics was also evaluated.

KAISER ALUMINUM ALLOY 7050

Alloy Digest ◽  
2000 ◽  
Vol 49 (1) ◽  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Heat Treating ◽  
High Fracture Toughness ◽  
High Fracture ◽  
Kaiser Aluminum ◽  
Structural Parts ◽  
Very High

Abstract Kaiser Aluminum Alloy 7050 has very high mechanical properties including tensile strength, high fracture toughness, and a high resistance to exfoliation and stress-corrosion cracking. The alloy is typically used in aircraft structural parts. This datasheet provides information on composition, physical properties, hardness, tensile properties, and shear strength as well as fracture toughness and fatigue. It also includes information on forming, heat treating, machining, and joining. Filing Code: AL-366. Producer or source: Tennalum, A Division of Kaiser Aluminum.

Influence of additive composition on thermal and mechanical properties of β–Si3N4 ceramics

2004 ◽  
Vol 19 (11) ◽  
pp. 3270-3278 ◽  
Author(s):  
Xinwen Zhu ◽  
Hiroyuki Hayashi ◽  
You Zhou ◽  
Kiyoshi Hirao
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Fracture Toughness ◽  
Nitrogen Pressure ◽  
High Fracture Toughness ◽  
Oxygen Impurity ◽  
Thermal And Mechanical Properties ◽  
High Fracture ◽  
Doped Materials ◽  
Gas Pressure Sintering

Dense β–Si3N4 ceramics were fabricated from α–Si3N4 raw powder by gas-pressure sintering at 1900 °C for 12 h under a nitrogen pressure of 1 MPa, using four different kinds of additive compositions: Yb2O3–MgO, Yb2O3–MgSiN2, Y2O3–MgO, and Y2O3–MgSiN2. The effects of additive composition on the microstructure and thermal and mechanical properties of β–Si3N4 ceramics were investigated. It was found that the replacement of Yb2O3 by Y2O3 has no significant effect on the thermal conductivity and fracture toughness, but the replacement of MgO by MgSiN2 leads to an increase in thermal conductivity from 97 to 113 Wm-1K-1and fracture toughness from 8 to 10 MPa m1/2, respectively. The enhanced thermal conductivity of the MgSiN2-doped materials is attributed to the purification of β–Si3N4 grain and increase of Si3N4–Si3N4 contiguity, resulting from the enhanced growth of large elongated grains. The improved fracture toughness of the MgSiN2-doped materials is attributed to the increase of grain size and fraction of large elongated grains. However, the same thermal conductivity between the Yb2O3- and Y2O3-doped materials is related to not only their similar microstructures, but also the similar abilities of removing oxygen impurity in Si3N4 lattice between Yb2O3 and Y2O3. The same fracture toughness between the Yb2O3- and Y2O3-doped materials is consistent with their similar microstructures. This work implies that MgSiN2 is an effective sintering aid for developing not only high thermal conductivity (>110 Wm−1K−1) but also high fracture toughness (>10 MPa m1/2) of Si3N4 ceramics.

scholarly journals Automatic Evaluation of the Mechanical Properties of Steels Maraging using Digital Image Processing Techniques

2020 ◽  
Author(s):  
Angélica Alves Viana ◽  
Savio Lopes Rabelo ◽  
José Daniel de Alencar Santos ◽  
Venceslau Xavier de Lima Filho ◽  
Douglas De Araújo Rodrigues ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Maraging Steel ◽  
Raw Material ◽  
High Fracture Toughness ◽  
Mechanical Resistance ◽  
High Fracture ◽  
Traditional System ◽  
Transformation Methods ◽  
Processing Techniques

Some strategic sectors of the economy require that the raw material of their machines and equipment have mechanical properties that satisfy their use. Maraging steel is a material of great concern since it is necessary to have a high mechanical resistance associated with high fracture toughness. The traditional tests to determine the fracture toughness of this material before use in applications are the Charpy and KIC tests. However, this process is characterized by being exhaustive and requiring specialized and trained professionals. Thus, to reverse this situation, this work proposes a new approach to determine the mechanical properties of maraging steel. For this, initially, the method removes any artifacts present in the image resulting from the mode of acquisition. In sequence, this works tested the method Extended Minimum Transformation (EMT) and mathematical morphology to find these markers of the regions of the dimples. Then, the Adaptive Thresholding, Optimal Global Thresholdusing the Otsu Method and Watershed transformation methods were used to segment the dimples. In the end, the diameter of the dimples and the toughness of the material were calculated. Tests are carried out and compared with the result obtained by specialists using the traditional system to evaluate the proposed approach. The results obtained were satisfactory for the application because the proposed approach presented speed and precision to the conventional methods.

Microstructure and Mechanical Properties of SiC Whisker-Reinforced ZrB2 Ultra-High Temperature Ceramic

2008 ◽  
Vol 368-372 ◽  
pp. 1730-1732 ◽  
Author(s):  
Ping Hu ◽  
Xing Hong Zhang ◽  
Jie Cai Han ◽  
Song He Meng ◽  
Bao Lin Wang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
High Temperature ◽  
Flexural Strength ◽  
Hot Pressing ◽  
Room Temperature ◽  
Pressing Temperature ◽  
Sintering Time ◽  
Microstructure And Mechanical Properties ◽  
Ultra High Temperature

SiC whisker-reinforced ZrB2 matrix ultra-high temperature ceramic were prepared at 2000°C for 1 h under 30MPa by hot pressing and the effects of whisker on flexural strength and fracture toughness of the composites was examined. The flexural strength and fracture toughness are 510±25MPa and 4.05±0.20MPa⋅m1/2 at room temperature, respectively. Comparing with the SiC particles-reinforced ZrB2 ceramic, no significant increase in both strength and toughness was observed. The microstructure of the composite showed that the SiC whisker was destroyed because the SiC whisker degraded due to rapid atom diffusivity at high temperature. The results suggested that some related parameters such as the lower hot-pressing temperature, a short sintering time should be controlled in order to obtain SiC whiskerreinforced ZrB2 composite with high properties.

An Investigation on Microstructures and Mechanical Properties of Ultra-Low Cu Layer Thickness Ratio Cu/8011/1060 Clads

2019 ◽  
Vol 50 (12) ◽  
pp. 5866-5876 ◽  
Author(s):  
Guoping Liu ◽  
Qudong Wang ◽  
Zhengping Shang ◽  
Liugen Luo ◽  
Bing Ye ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Layer Thickness ◽  
Thickness Ratio ◽  
Layer Thickness Ratio ◽  
Microstructures And Mechanical Properties

Al2O3/ZrO2 (Y2O3) PREPARED BY COMBUSTION SYNTHESIS UNDER HIGH GRAVITY

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1148-1153 ◽  
Author(s):  
LONG ZHANG ◽  
ZHONGMIN ZHAO ◽  
YIGANG SONG ◽  
WEIGUO WANG ◽  
HONGBO LIU
Keyword(s):  
Fracture Toughness ◽  
Flexural Strength ◽  
Combustion Synthesis ◽  
High Fracture Toughness ◽  
High Gravity ◽  
Transformation Toughening ◽  
Composite Ceramics ◽  
Directionally Solidified ◽  
High Fracture ◽  
Toughening Mechanisms

By introducing ZrO 2 (4 Y ) powder into the thermit, Al 2 O 3/ ZrO 2 (4 Y ) composite ceramics of different composition and microstructures were prepared through combustion synthesis under high gravity, and the correlations of composition, microstructures and mechanical properties of composite ceramics were investigated. The results of XRD, SEM and EDS showed that Al 2 O 3/33% ZrO 2 (4 Y ) were composed of random-orientated rod-shaped colonies consisting of a triangular dispersion of orderly submicron-nanometer t - ZrO 2 fibers, surrounded by inter-colony regions consisting of spherically-shaped micronmeter t - ZrO 2 grains; meanwhile, Al 2 O 3/45% ZrO 2 (4 Y ) were comprised of spherically-shaped micron-meter t - ZrO 2 grains. Similar to the international directionally solidified Al 2 O 3/ ZrO 2 ( Y 2 O 3), the EDS results also indicated that there are no impurities, amorphous phases and grain boundaries but clean phase interfaces in two ceramic composites. Compared to the international directionally solidified Al 2 O 3/ ZrO 2 ( Y 2 O 3), the increase in hardness and flexural strength of Al 2 O 3/33% ZrO 2 (4 Y ) in the experiment was due to small-size defect and high fracture toughness induced by compressive residual stress effect and transformation toughening mechanisms; meanwhile, high flexural strength of Al 2 O 3/45% ZrO 2 (4 Y ) was considered to be a result of the fine spherically-shaped t - ZrO 2 grains separated from the melt under high gravity, and high fracture toughness induced by transformation toughening and micro-crack toughening mechanisms.

Preparation of a Novel Poly(Methyl Methacrylate)-Dimethyl Diethoxysilane Nano-Composite

2007 ◽  
Vol 361-363 ◽  
pp. 491-494 ◽  
Author(s):  
Kyu Hyeon Lee ◽  
Yong Keun Lee ◽  
Bum Soon Lim ◽  
Sung Baek Cho ◽  
Sang Hoon Rhee
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Methyl Methacrylate ◽  
Bone Cement ◽  
Tetraethyl Orthosilicate ◽  
High Fracture Toughness ◽  
High Fracture ◽  
Nano Composite ◽  
Poly Methyl Methacrylate

The poly(methyl methacrylate)/silica nano-composite made from trimethoxysilyl functionalized poly(methyl methacrylate) and dimethyl diethoxysilane was newly prepared and its apatite-forming ability and mechanical properties were evaluated comparing to poly(methyl methacrylate)/silica nano-composite made from trimethoxysilyl functionalized poly(methyl methacrylate) and tetraethyl orthosilicate. Its apatite-forming ability was similar to that of poly(methyl methacrylate)/silica nano-composite using tetraethyl orthosilicate but its fracture toughness was much improved. Its high fracture toughness might come from the less quantity of siloxane linkages in its structure because dimethyl diethoxysilane had only two ethoxysilane groups while tetraethyl orthosilicate had four ethoxysilane groups. From the results, it can be concluded that it has a possibility to be used as bioactive bone cement.

Correlation between microstructure and mechanical properties in silicon carbide with alumina addition

1993 ◽  
Vol 8 (7) ◽  
pp. 1635-1643 ◽  
Author(s):  
S.S. Shinozaki ◽  
J. Hangas ◽  
K.R. Carduner ◽  
M.J. Rokosz ◽  
K. Suzuki ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Silicon Carbide ◽  
Analytical Electron Microscopy ◽  
High Strength ◽  
High Fracture Toughness ◽  
Sintered Body ◽  
High Fracture ◽  
High Fatigue ◽  
Alumina Addition

The microstructure of pressureless sintered silicon carbide (SiC) materials with alumina (Al2O3) addition was investigated using analytical electron microscopy and nuclear magnetic resonance. A sintered body with a density of higher than 99% theoretical was obtained with an addition of 5 wt.% Al2O3. The sintered body (SiC–Al2O3) has high strength, high fracture toughness, and high fatigue resistance. Its fracture toughness is approximately 5 MPa-m1/2, which is twice as high as that of pressureless sintered SiC materials with boron and carbon additions (SiC–B–C). The correlation between the microstructure and the mechanical properties is presented here. The starting β–SiC powder is mostly transformed to α–SiC with various polytype distributions during the sintering process. The microstructure has homogeneously distributed, fine, plate-like interlocking gains with a high aspect ratio. Well-developed basal planes form parallel and elongated boundaries, and the crystal structure is mostly the 6H polytype (56%) mixed with thin lamellar 4H.

Microstructural evolution and mechanical properties of gas-pressure-sintered Si3N4 with Yb2O3 as a sintering aid

1999 ◽  
Vol 14 (5) ◽  
pp. 1904-1909 ◽  
Author(s):  
Ki-Min Lee ◽  
Won-Ho Lee ◽  
Young-Hag Koh ◽  
Jong-Jin Choi ◽  
Hyoun-Ee Kim ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Microstructural Evolution ◽  
Outer Region ◽  
Functionally Graded ◽  
Gas Pressure ◽  
High Fracture Toughness ◽  
High Fracture ◽  
Sintering Aid ◽  
Inner Region

Microstructural evolution and mechanical properties of gas-pressure-sintered Si3N4 with 4 wt% Yb2O3 as a sintering aid were investigated. The microstructure was not uniform throughout the specimen. Extremely large elongated grains were formed at the outer region near the surface, while relatively small elongated grains were formed at the inner region of the specimen. The outer region expanded inward with the sintering time. Mechanical properties, such as flexural strength, fracture toughness, and R-curve behavior of the specimens were strongly influenced by these variations in microstructure. The fracture toughness and the R-curve behavior of the outer region were higher than those of the inner region of the same specimen. On the other hand, the strength of the inner region was higher than that of the outer region. By controlling the relative thickness of each region, Si3N4 specimens having functionally graded microstructure were obtained. The Si3N4 with such microstructure exhibited high strength, high fracture toughness, and good flaw tolerance at the same time.

Large Scale Al2O3-ZrO2 (Y2O3) Eutectic and Hypereutectic Achieved by Combustion Synthesis in High Gravity Field

2014 ◽  
Vol 602-603 ◽  
pp. 252-257
Author(s):  
Xiao Bo Lu ◽  
Hong Bo Liu ◽  
Yu Fei Zhang
Keyword(s):  
Fracture Toughness ◽  
Flexural Strength ◽  
Gravity Field ◽  
Combustion Synthesis ◽  
Ceramic Composites ◽  
High Fracture Toughness ◽  
High Gravity ◽  
Transformation Toughening ◽  
High Fracture ◽  
High Gravity Field

By introducing ZrO2 (4Y) powder into the thermit, the solidified Al2O3-ZrO2 (4Y) ceramic composites with eutectic and hypereutectic microstructures were prepared via combustion synthesis in high gravity field, and the microstructures and mechanical properties of the solidified ceramic composites were discussed. XRD, SEM and EDS showed that the Al2O3-33%ZrO2 (4Y) as the eutectic were composed of random-orientated rod-shaped colonies consisting of a triangular dispersion of orderly submicron-nanometer t-ZrO2 fibers, surrounded by inter-colony regions consisting of spherically-shaped micrometer t-ZrO2 grains, whereas Al2O3-45%ZrO2 (4Y) as the hypereutectic were comprised of spherically-shaped micron-meter t-ZrO2 grains, surround by irregularly-shaped α-Al2O3 grains and a few colonies. Compared to the directionally solidified Al2O3-ZrO2 (Y2O3), the increase in hardness and flexural strength of the eutectic obtained in current experiment was due to high densification, small-size defect and high fracture toughness induced by residual stress toughening and transformation toughening mechanisms; meanwhile, in despite of the moderate decrease in hardness, high flexural strength of the hypereutectic was considered to be a result of small-size defect and high fracture toughness induced by transformation toughening and microcrack toughening mechanisms.

Sign in / Sign up

Export Citation Format

Share Document