scholarly journals Microstructure and Mechanical Properties of ZrB2–HfC Ceramics Influenced by HfC Addition

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2046 ◽  
Author(s):  
Yi Jing ◽  
Hongbing Yuan ◽  
Zisheng Lian
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Grain Boundaries ◽  
Sintering Temperature ◽  
Liquid Phase Sintering ◽  
Weak Interface ◽  
Interface Bonding ◽  
Microstructure And Mechanical Properties ◽  
Small Grains

ZrB2–HfC ceramics have been fabricated using the liquid phase sintering technique at a sintering temperature as low as 1750 °C through the addition of Ni. The effects of HfC addition on the microstructure and mechanical properties of ZrB2–based ceramics have been investigated. These ceramics were composed of ZrB2, HfC, Ni, and a small amount of possible (Zr, Hf)B2 solid solution. Small HfC grains were distributed among ZrB2 grain boundaries. These small grains could improve the density of ZrB2–based ceramics and play a pinning role. With HfC content increasing from 10 wt % to 30 wt %, more HfC grains were distributed among ZrB2 grain boundaries, leading to weaker interface bonding among HfC grains; the relative density and Vickers hardness increased, and flexural strength and fracture toughness decreased. The weak interface bonding for 20 and 30 wt % HfC contents was the main cause of the decrease in both flexural strength and fracture toughness.

Effect of Iron Additive on the Sintering Behavior of Hot-Pressed ZrC-W Composites

2008 ◽  
Vol 368-372 ◽  
pp. 1764-1766 ◽  
Author(s):  
Yu Jin Wang ◽  
Lei Chen ◽  
Tai Quan Zhang ◽  
Yu Zhou
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Relative Density ◽  
Sintering Temperature ◽  
Sintering Behavior ◽  
Hot Press ◽  
Sintering Additive ◽  
Microstructure And Mechanical Properties ◽  
Hot Press Sintering

The ZrC-W composites with iron as sintering additive were fabricated by hot-press sintering. The densification, microstructure and mechanical properties of the composites were investigated. The incorporation of Fe beneficially promotes the densification of ZrC-W composites. The relative density of the composite sintered at 1900°C can attain 95.3%. W2C phase is also found in the ZrC-W composite sintered at 1700°C. The content of W2C decreases with the increase of sintering temperature. However, W2C phase is not identified in the composite sintered at 1900°C. The flexural strength and fracture toughness of the composites are strongly dependent on sintering temperature. The flexural strength and fracture toughness of ZrC-W composite sintered at optimized temperature of 1800°C are 438 MPa and 3.99 MPa·m1/2, respectively.

Influence of Hot Pressing Sintering Temperature and Time on Microstructure and Mechanical Properties of TiB2/Al2O3 Tool Materials

2012 ◽  
Vol 500 ◽  
pp. 629-633 ◽  
Author(s):  
Mei Lin Gu ◽  
Hong Jing Xu ◽  
Jian Hua Zhang ◽  
Zhi Wei
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Hot Pressing ◽  
Sintering Temperature ◽  
Three Point Bending ◽  
Sintering Time ◽  
Microstructure And Mechanical Properties ◽  
Hot Pressing Sintering ◽  
Increasing Temperature

In this paper, a TiB2/Al2O3composite was hot-pressed. The effect of hot pressing parameters on the TiB2/Al2O3composite microstructure and mechanical properties was investigated. The flexural strength and fracture toughness were measured by three point bending testing and direct indentation method, respectively. Experimental results show that the flexural strength decreases consistently with an increase in the sintering time, however, the fracture toughness increases consistently with an increase in the sintering time and sintering temperature. The maximum of the flexural strength is 1072 MPa at 1530 sintering temperature and 60 min sintering time. The microstructures were revealed by means of SEM. The results show that the TiB2grain size and density increases with the increasing temperature and time during hot pressing sintering, which benefits the fracture toughness and flexural strength.

scholarly journals Microstructure and mechanical properties of Ti3SiC2 MAX phases sintered by hot pressing

2021 ◽  
Vol 1 (4) ◽  
pp. 216-222
Author(s):  
Sheida Haji Amiri ◽  
Nasser Pourmohammadie Vafa
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Vickers Hardness ◽  
Hot Pressing ◽  
Sintering Temperature ◽  
Sintered Sample ◽  
Max Phases ◽  
Microstructure And Mechanical Properties ◽  
Fine Grained Structure

The Ti3SiC2 used in this project has been purchased ready-made. This study aimed to investigate the effect of sintering temperature on samples' microstructure and mechanical properties, including three-point flexural strength, Vickers hardness, and fracture toughness. Therefore, Ti3SiC2 samples were sintered under a vacuum atmosphere at a pressure of 35 MPa for 30 minutes at two temperatures of 1500 °C and 1550 °C by hot pressing. The microstructure obtained from the fracture cross-section of the samples shows that by increasing the sintering temperature to 1550 °C, the microstructure of this sample becomes larger than the sintered sample at 1500 °C. Also, increasing the sintering temperature to 1550 °C causes the decomposition of Ti3SiC2 to TiC, which can be seen in the X-ray diffraction pattern (XRD). In addition, the relative density of the sintered sample at 1550 °C is 98.08% which is higher than that of the sintered sample at 1500 °C with the result of 89%. On the other hand, the three-point flexural strength (227.5 MPa), the Vickers hardness (~9 GPa), and the fracture toughness (8.6 MPa.m1/2) of the sintered sample at 1500 °C are higher due to the fine-grained structure.

Effect of Sintering Temperature on Microstructure and Mechanical Properties of Al2O3-TiC-ZrO2 Ceramic Composites

2012 ◽  
Vol 476-478 ◽  
pp. 1031-1035
Author(s):  
Wei Min Liu ◽  
Xing Ai ◽  
Jun Zhao ◽  
Yong Hui Zhou
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Relative Density ◽  
Sintering Temperature ◽  
Ceramic Composites ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

Al2O3-TiC-ZrO2ceramic composites (ATZ) were fabricated by hot-pressed sintering. The phases and microstructure of the composites were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The relative density and mechanical properties (flexural strength, fracture toughness and Vicker’s hardness) of the composites were tested. The results show that the microstructure of the composites was the gray core-white rim. With the increase of sintering temperature, the relative density and mechanical properties of the composites increased first and then decreased. The composite sintered at 1705°C has the highest synthetical properties, and its relative density, flexural strength, fracture toughness and Vickers hardness are 98.3%,970MPa,6.0 MPa•m1/2and 20.5GPa, respectively.

Effects of Sintering Additives on the Microstructure and Mechanical Properties of Silicon Nitride Ceramics by GPS

2010 ◽  
Vol 105-106 ◽  
pp. 27-30 ◽  
Author(s):  
Wei Ru Zhang ◽  
Feng Sun ◽  
Ting Yan Tian ◽  
Xiang Hong Teng ◽  
Min Chao Ru ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Phase Transformation ◽  
Silicon Nitride ◽  
Porous Silicon ◽  
Flexural Strength ◽  
Relative Density ◽  
Sintering Additives ◽  
Microstructure And Mechanical Properties ◽  
Nitride Ceramics

Silicon nitride ceramics were prepared by gas pressure sintering (GPS) with different sintering additives, including La2O3, Sm2O3 and Al2O3. Effect of sintering additives on the phase-transformation, microstructure and mechanical properties of porous silicon nitride ceramics was investigated. The results show that the reaction of sintering additives each other and with SiO2 had key effects on the phase-transformation, grain growing and grain boundaries. With 9MPa N2 atmosphere pressure, holding 1h at 1850°C, adding 10wt% one of the La2O3, Sm2O3, Al2O3, porous silicon nitride was prepared and the relative density was 78%, 72%, 85% respectively. The flexural strength was less than 500MPa, and the fracture toughness was less than 4.8MPam1/2. Dropping compounds sintering additives, such as La2O3+Al2O3, Sm2O3+Al2O3 effectively improves the sintering and mechanical properties. The relative density was 99.2% and 98.7% with 10wt% compounds sintering additives. The grain ratio of length to diameter was up to 1:8. The flexural strength was more than 900MPa, and the fracture toughness was more than 8.9MPam1/2.

Thermal Conductivity of Si₃N₄ Ceramics Fabricated From Carbothermal-reduction-derived Powder

2021 ◽  
Author(s):  
Yuelong Wang ◽  
Xingyu Li ◽  
Haoyang Wu ◽  
Baorui Jia ◽  
Deyin Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Fracture Toughness ◽  
Grain Size ◽  
Flexural Strength ◽  
Grain Boundaries ◽  
Carbothermal Reduction ◽  
Secondary Phase ◽  
Gas Pressure ◽  
Gas Pressure Sintering

Abstract Si3N4-based ceramic (Si3N4-5wt%Y2O3-3wt%MgO) was obtained from carbothermal-reduction-derived powder combined with gas pressure sintering. The phase, microstructure, thermal conductivity and mechanical properties of Si3N4 ceramics were comprehensively analyzed. Dense Si3N4 ceramic with uniform grain size was obtained after sintering at 1900°C for 7 h under a N2 pressure of 1.2 MPa. The secondary phase consisted of Y4Si2O7N2 and Y2Si3O3N4 was found to gather around triangular grain boundaries. The thermal conductivity, flexural strength, hardness and fracture toughness of the Si3N4 ceramics were 95.7 W·m-1·k-1, 715 MPa, 17.2 GPa and 7.2 MPa·m1/2, respectively. The results were compared with product derived from commercial powder, the improvement of thermal conductivity (~8.3%) and fracture toughness (~4.3%) demonstrating the superiority of Si3N4 ceramics prepared from carbothermal-reduction-derived powder.

scholarly journals Preparation and Performance of Al2O3/Ti(C,N)-Added ZrO2 Whisker and NanoCoated CaF2@Al(OH)3 Powder

2020 ◽  
Vol 10 (13) ◽  
pp. 4435
Author(s):  
Qi Li ◽  
Guangchun Xiao ◽  
Zhaoqiang Chen ◽  
Runxin Guo ◽  
Mingdong Yi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Phase Transition ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Ceramic Material ◽  
Microstructure And Mechanical Properties ◽  
And Performance

The Al2O3/Ti(C,N) ceramic material added micron ZrO2 whisker and nano coated CaF2@Al(OH)3 powder was fabricated. The micron ZrO2 whisker was for the toughening and reinforcing phase and the nano coated CaF2@Al(OH)3 powder was the lubricant. For obtaining a ceramic material with optimal comprehensive mechanical properties and friction properties, the influences of different compositions of the ZrO2 whisker and nano coated CaF2@Al(OH)3 powder on the microstructure and mechanical properties were analyzed, respectively. The result demonstrated that as the addition of the ZrO2 whisker was 6 vol% and the addition of the nano coated CaF2@Al(OH)3 powder was 10 vol%, the optimal self-lubricating ceramic material had optimal mechanical properties. The hardness of the ceramic material was 16.72 GPa, the flexural strength was 520 MPa and the fracture toughness reached 7.16 MPa·m1/2. The formation of the intragranular structure, whisker toughening and the phase transition of ZrO2 were the main mechanisms.

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.

Effects of Nano-ZrO2 on the Microstructure and Mechanical Properties of Ti(C,N)-Based Cermet Die Materials

2010 ◽  
Vol 154-155 ◽  
pp. 1319-1323 ◽  
Author(s):  
Xing Hai Wang ◽  
Chong Hai Xu ◽  
Ming Dong Yi ◽  
Hui Fa Zhang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Electron Microscope ◽  
Flexural Strength ◽  
Weight Percent ◽  
Environmental Scanning ◽  
Microstructure And Mechanical Properties ◽  
Vacuum Atmosphere ◽  
Die Materials ◽  
Scanning Electron

In recent, the development of new die materials is one of the important topics in the field of die research. In this paper, effects of nano-ZrO2 addition on the microstructure and mechanical properties of Ti(C,N)-based cermets were studied. The newly developed Ti(C,N)-based cermet die materials with different contents of nano-ZrO2 of 0~25wt% were prepared by hot pressing technique under vacuum atmosphere at 1450°C for 30min. Moreover, the microstructure of this Ti(C,N)-based cermet die materials was observed by environmental scanning electron microscope. It indicates that the comprehensive mechanical properties can reach the optimum when the weight percent of the nano-ZrO2 is 10%. The corresponding flexural strength and fracture toughness is 967 MPa and 13.62 MPa•m1/2, respectively which is approximately 65% and 110% higher than that of the cermet without nano-ZrO2 addition. It suggests that the addition of nano-ZrO2 can improve the mechanical properties especially the fracture toughness and flexural strength of Ti(C,N)-based cermet die materials.

Microstructure and Mechanical Properties of Hot Pressed ZrC-SiC-ZrB2 Composites

2010 ◽  
Vol 434-435 ◽  
pp. 173-177 ◽  
Author(s):  
Bao Xia Ma ◽  
Wen Bo Han ◽  
Xing Hong Zhang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Size ◽  
Flexural Strength ◽  
Hot Pressing ◽  
Ceramic Composites ◽  
Strong Function ◽  
Slight Tendency ◽  
Microstructure And Mechanical Properties

Ternary ZrC-SiC-ZrB2 ceramic composites were prepared by hot pressing at 1900 °C for 60 min under a pressure of 30 MPa in argon. The influence of ZrB2 content on the microstructure and mechanical properties of ZrC-SiC-ZrB2 composites was investigated. Examination of SEM showed that the microstructure of the composites consisted of the equiaxed ZrB2, ZrC and SiC grains, and there was a slight tendency of reduction for grain size in ZrC with increasing ZrB2 content. The hardness increased considerably from 23.3 GPa for the ZS material to 26.4 GPa for the ZS20B material. Flexural strength was a strong function of ZrB2 content, increasing from 407 MPa without ZrB2 addition to 627 MPa when the ZrB2 content was 20vol.%. However, the addition of ZrB2 has little influence on the fracture toughness, ranging between 5.5 and 5.7 MPam1/2.

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