scholarly journals Fabrication and mechanical properties of self-toughening ZrB2–SiC composites from in-situ reaction

2019 ◽  
Vol 8 (4) ◽  
pp. 527-536 ◽  
Author(s):  
Zhaofu Zhang ◽  
Jianjun Sha ◽  
Yufei Zu ◽  
Jixiang Dai ◽  
Yingjun Liu
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Hot Pressing ◽  
High Fracture Toughness ◽  
High Fracture ◽  
Microstructure Observation ◽  
Pull Out ◽  
Sic Composites ◽  
Reactive Hot Pressing

AbstractSelf-toughening ZrB2–SiC based composites are fabricated by in-situ reactive hot pressing. The effect of sintering additive content on the microstructure and mechanical properties of the composites is investigated. Microstructure observation found that the in-situ reactive hot pressing could promote the anisotropic growth of ZrB2 grains and the formation of interlocking microstructure. Such microstructure could improve the mechanical properties, especially, for the fracture toughness. The improved mechanical properties could be attributed to the self-toughening structure related to the ZrB2 platelets and the formed interlocking microstructure, which could trigger various toughening mechanisms such as grain pull-out, crack bridging, crack deflection, and crack branching, providing the main contribution to the high fracture toughness.

Fracture Energy and Fracture Toughness of In Situ Calcium Hexaluminate (CA6)-Alumina Monolithic Refractory

2018 ◽  
Vol 766 ◽  
pp. 77-82
Author(s):  
Jiraprabha Khajornboon ◽  
Kouichiro Washijima ◽  
Takeshi Shiono
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Fracture Energy ◽  
Raw Materials ◽  
Stoichiometric Composition ◽  
Physical And Mechanical Properties ◽  
Apparent Porosity ◽  
High Fracture Toughness ◽  
High Fracture

One of main raw materials for monolithic refractory is calcium aluminate cement which provides CA6 hexagonal plate-like microstructure with self-toughening properties and fracture resistance. In the present study, in-situ CA6 was formed by using sintered alumina mixing with alumina cement in stoichiometric composition to achieve 100 mass% and 50 mass% of CA6 in alumina monolithic refractory with 2 mass% of silica addition. Samples were fired from 1400-1500°C for 5 h and characterized for physical and mechanical properties. The results showed that both samples could not obtain CA6 content as expected and apparent porosity did not exhibit in the same tendency. However, only proper amount of CA6 content could gain proper amount of apparent porosity which is the main effect of mechanical properties. Especially the formation of CA6 lower than 50 mass% with the presence of low melting phase caused low apparent porosity and led to high fracture toughness and effective fracture energy.

Microstructure and Mechanical Properties of ZrB2-Based UHTC via Reactive Hot Pressing

2008 ◽  
Vol 368-372 ◽  
pp. 1737-1739
Author(s):  
Qiang Qu ◽  
Wen Bo Han ◽  
Song He Meng ◽  
Xing Hong Zhang ◽  
Jie Cai Han
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Fracture Toughness ◽  
High Temperature ◽  
Hot Pressing ◽  
Sintering Temperature ◽  
Volume Ratio ◽  
Ultra High Temperature Ceramics ◽  
Reactive Hot Pressing

ZrB2-based ultra-high temperature ceramics (UHTCs) were prepared from a mixture powder of Zr/B4C/Si with different ratio via reactive hot pressing. The experimental results showed that the sintering temperature above 1800°C was necessary for enhancing the activity of the powders and thus improving the densification of the product. The sinterability and densification properties of ZrB2-based UHTCs meliorated with the amount of Si increasing. However, many large ZrB2 agglomerates formed when the amount of synthesized SiC in the product reached 25vol%, which led to decrease the mechanical property. The composite had highest mechanical properties when the volume ratio of ZrB2: SiC: ZrC was 73.86:20:6.14, and its flexual strength and the fracture toughness were 645.8MPa and 5.66MPa·m1/2 respectively. The microstructure investigation showed the in-situ formed SiC and ZrC were located in the triple point of ZrB2 grains with a size less than 3μm.

Effect of TiC Content on the Microstructure and Mechanical Properties of Ti3AlC2/Al2O3 In Situ Composites Synthesized by Hot Pressing

2012 ◽  
Vol 724 ◽  
pp. 278-281 ◽  
Author(s):  
Lan Ye ◽  
Jian Feng Zhu
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Phase Composition ◽  
Flexural Strength ◽  
High Temperatures ◽  
Vickers Hardness ◽  
Hot Pressing ◽  
Microstructure And Mechanical Properties ◽  
Reactive Hot Pressing

The Ti3AlC2/Al2O3 in situ composites were successfully synthesized from the system of Ti-TiC-Al-TiO2 by reactive hot pressing at 1350 °C. The effect of TiC content on the phase composition, microstructure and mechanical properties were investigated in detail. The results indicate that the fabricated products possess the highest purity as the TiC contents reduce to 90 % of its theoretical content. This deviation is mainly attributed to the decomposition of Ti3AlC2 and vaporization of Al at high temperatures. The effect of TiC content on the fracture toughness, flexural strength, Vickers hardness of Ti3AlC2/Al2O3 composites was also discussed in detail.

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.

In-situ Synthesis of Si3N4/SiC Composites by Reactive Hot-Pressing from Elemental Powders

1998 ◽  
Vol 161-163 ◽  
pp. 63-66 ◽  
Author(s):  
H. Tsuda ◽  
T. Ohtsuka ◽  
Hiroshi Mabuchi ◽  
K. Morii
Keyword(s):  
Hot Pressing ◽  
In Situ Synthesis ◽  
Sic Composites ◽  
Reactive Hot Pressing

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.

scholarly journals The effect of various Co contents on the microstructure and properties of Ti(C,N)-TiB2-Co cermets prepared in situ via reactive hot pressing

2020 ◽  
Vol 12 (5) ◽  
pp. 168781402092571
Author(s):  
Xianrui Zhao ◽  
Ze Yu ◽  
Dunwen Zuo ◽  
Qintao Li ◽  
Mengxian Zhang ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Relative Density ◽  
Vickers Hardness ◽  
Hot Pressing ◽  
Hardness Test ◽  
Reactive Hot Pressing ◽  
Compacting Pressure ◽  
Vickers Hardness Test ◽  
Scanning Electron

Ti(C,N)-TiB2-Co cermets were in situ synthesized, via reactive hot pressing from the Co-Ti-C-BN system, with a Co content ranging from 6 to 22 wt%. The microstructure, relative density, hardness, and fracture toughness of the sintered compacts was investigated by light microscopy, scanning electron microscopy, ceramic densitometry, and Vickers hardness test. The investigations indicate that during hot pressing (compacting pressure = 30 MPa), when the Co content is 14–22 wt%, the metal binder is extruded. Co and Ti are included in the extrudate, breaking the original ratio and deteriorating the properties of the sintered products. As the Co content increases from 6 wt% to 12 wt%, the porosity increases, and the relative density increases from 97.2% to 99.5%. The fracture toughness increases from 6.1 to 6.8 MPa m1/2. The Vickers hardness first increases from 1897 HV10 to the maximum 1960 HV10 and then decreases slightly to 1945 HV10.

Reactive Synthesis and Mechanical Properties of ZrB2-SiC-ZrC Composites

2008 ◽  
Vol 368-372 ◽  
pp. 1758-1760 ◽  
Author(s):  
Wen Wen Wu ◽  
Guo Jun Zhang ◽  
Yan Mei Kan ◽  
Pei Ling Wang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Hot Pressing ◽  
Raw Materials ◽  
Reactive Synthesis ◽  
Reactive Hot Pressing

ZrB2-SiC based composites with 0,5 and 15 vol% addition of ZrC were synthesized via reactive hot pressing at 1800°C using Zr, Si and B4C as raw materials. The mechanical properties of the composites were investigated. The composite of ZSC15 that contained 15 vol% of ZrC has the highest hardness. ZSC5 with 5 vol% of ZrC owns a most homogenous microstructure and the highest fracture toughness and flexural strength.

Sign in / Sign up

Export Citation Format

Share Document