Mechanical Properties of ZrB2-Based Ceramics Reinforced by Nano-SiC Whiskers

2007 ◽  
Vol 353-358 ◽  
pp. 1564-1567 ◽  
Author(s):  
Hai Long Wang ◽  
Chang An Wang ◽  
Rui Zhang ◽  
Xing Hu ◽  
Dai Ning Fang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Size ◽  
Relative Density ◽  
Hot Pressing ◽  
Bending Strength ◽  
Sintering Process ◽  
Homogeneous Microstructure ◽  
Sic Whiskers ◽  
Xrd Techniques

In this paper, ZrB2-based ceramics containing up to 15 vol% nano-SiC whiskers were prepared by hot pressing at 1950°C under 20MPa pressure in flow argon. SEM and XRD techniques were used to characterize the sintered compacts. A fine and homogeneous microstructure was observed. The relative density of ZrB2-based ceramic containing 10vol% SiC whiskers reached to 97.7%. The bending strength and fracture toughness of the composite were 550 MPa and 8.08 MPa·m1/2 respectively, while those of the monolithic ZrB2 ceramic (0 vol% SiC whiskers added) were 424 MPa and 4.52 MPa·m1/2 respectively. The grain size of the ZrB2-based ceramics was reduced greatly by the addition of nano-SiC whiskers during the sintering process.

Effects of Ti(C,N) Nanoparticles on Mechanical Properties of the Si3N4 Ceramics

2011 ◽  
Vol 80-81 ◽  
pp. 119-122
Author(s):  
Qian Li ◽  
Fu Sheng Zhu ◽  
Zhi Meng Xiu ◽  
Xu Dong Sun
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Aspect Ratio ◽  
Relative Density ◽  
Hot Pressing ◽  
Bending Strength ◽  
Lateral Growth ◽  
Toughening Mechanism ◽  
Vacuum Sintering ◽  
Crack Bridging

Si3N4-Ti(C,N) nanocomposites fabricated by vacuum hot pressing with Al2O3 and Y2O3 as additives were investigated. The results showed that the α-Si3N4 phase converted completely into whisker-shaped β-Si3N4 grains after vacuum sintering at 1700°C. Suitable addition and well dispersion of the Ti(C,N) particles can restrained the lateral growth of the β-Si3N4 grains, increasing aspect ratio of the β-Si3N4 grains and improving bending strength of the composites. Fracture toughness of the composites is higher than that of the β-Si3N4 ceramics, and the main toughening mechanism is crack bridging due to the higher aspect ratio of the β-Si3N4 grains.With the addition of 1vol% of Ti(C,N), the composite has a relative density of 99.31%, Vicker’s hardness of 15.9 GPa, bending strength of 993 MPa, and fracture toughness of 9.9 MPa·m1/2.

Effects of vanadium alloying on the microstructures and mechanical properties of hot-pressed tungsten material

2016 ◽  
Vol 30 (12) ◽  
pp. 1650216 ◽  
Author(s):  
Wei Guo ◽  
Kameel Arshad ◽  
Yue Yuan ◽  
Ming-Yue Zhao ◽  
Xiao-Lin Shu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Relative Density ◽  
Phase Formation ◽  
Hot Pressing ◽  
Bending Strength ◽  
Microstructures And Mechanical Properties ◽  
Tungsten Material

Tungsten and vanadium (W–V) alloys (with 1, 5 and 10 wt.% V) are fabricated by hot pressing (HP) at 1800[Formula: see text]C under 20 MPa for 2 h. The effects of V content on the microstructures and mechanical properties of W–V alloy are investigated. The results indicate that with increasing V content, (i) the formation of W–V alloying phase is enhanced and the grain size of W-matrix is significantly refined; (ii) the relative density gradually increases from 92.16% to 97.72% in the case of pure W to W-10 wt.% V; (iii) the hardness rises linearly while the bending strength decreases, which is related to the enhanced alloy phase formation.

Mechanical Properties and Oxidation Resistance of Hot Pressed B4C Ceramics Material

2011 ◽  
Vol 233-235 ◽  
pp. 2272-2275
Author(s):  
Xin Yan Yue ◽  
Bi Shuang Chen ◽  
Jing Zhao ◽  
Hong Qiang Ru ◽  
Wei Wang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Relative Density ◽  
Oxidation Resistance ◽  
Vickers Hardness ◽  
Hot Pressing ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Experimental Results ◽  
Pressing Method

B4C ceramics were obtained using hot-pressing method. The effect of different sintering temperatures on the microstructures and mechanical properties of B4C ceramics were investigated. Oxidation resistances were studied over the range 600-850°C. The experimental results showed that the relative density, bending strength and fracture toughness all increased first and then decreased with increasing the sintering temperature. The Vickers-hardness increased as the sintering temperature increasing. When the sintering temperature was 1950°C, the B4C ceramics showed the optimized properties. The values of its relative density, Vickers-hardness, bending strength and fracture toughness were 99.1%, 34.0 GPa, 524.6 MPa and 6.56 MPa·m1/2, respectively.

Fabrication of Carbon Nanotube Reinforced Boron Carbide Composite by Hot-Pressing Following Extrusion Molding

2014 ◽  
Vol 616 ◽  
pp. 27-31 ◽  
Author(s):  
Tomohiro Kobayashi ◽  
Katsumi Yoshida ◽  
Toyohiko Yano
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Elastic Modulus ◽  
Carbon Nanotube ◽  
Boron Carbide ◽  
Vickers Hardness ◽  
Hot Pressing ◽  
Bending Strength ◽  
Extrusion Direction ◽  
Sem Observation

The CNT/B4C composite with Al2O3 additive was fabricated by hot-pressing following extrusion molding of a CNT/B4C paste, and mechanical properties of the obtained composite were investigated. Many CNTs in the composite aligned along the extrusion direction from SEM observation. 3-points bending strength of the composite was slightly lower than that of the monolithic B4C. Elastic modulus and Vickers hardness of the composite drastically decreased with CNT addition. Fracture toughness of the composite was higher than that of the monolithic B4C.

Pressureless Sintering and Properties Investigation of Silicon Nitride

2011 ◽  
Vol 194-196 ◽  
pp. 1464-1469
Author(s):  
Bin Li ◽  
Yi Feng ◽  
Hui Qiang Liu ◽  
Yan Fang Zhu ◽  
Dong Bo Yu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Size ◽  
Bending Strength ◽  
Fracture Morphology ◽  
Pressureless Sintering ◽  
Sintering Aids ◽  
Α Phase ◽  
Different Grain Size ◽  
Si3n4 Ceramics

Different grain size of starting powder was choosed and different sintering additives were used to fabricate Si3N4 ceramics by pressureless sintering. Samples’ relative density and mechanical properties including Vickers hardness, bending strength and fracture toughness were tested. Then XRD, SEM and EDS were carried out to identify phase and observe microstructure and fracture morphology. The result shows that high purity α phase Si3N4 powder of 5 μm is suitable for sintering and combination of 5 wt.% MgO +5 wt.% Y2O3 is most effective within six kinds of sintering aids.

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.

Simultaneous Synthesis and Sintering of Al2O3/Mo2N Composites Using Capsule-Free Nitrogen Hot Isostatic Pressing and their Characterization

2010 ◽  
Vol 62 ◽  
pp. 197-202
Author(s):  
Hirota Ken ◽  
Takaoka Katsuya ◽  
Murase Yasushi ◽  
Kato Masaki
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Size ◽  
Vickers Hardness ◽  
Bending Strength ◽  
Hot Isostatic Pressing ◽  
Isostatic Pressing ◽  
Simultaneous Synthesis ◽  
Powder Compacts ◽  
Al2o3 Matrix

Synthesis of dense materials with the compositions of Al2O3/Mo2N=100/0 ~ 40/60 vol% has been attempted directly from Al2O3/Mo mixed raw powder compacts using capsule-free N2 hot isostatic pressing (HIP). During HIPing [1500°C/(16~20)MPa]/1h], solid/gas reaction between Mo and N2 was introduced to form Mo2N. Most sintered composites consisting of only Al2O3 and Mo2N phases reached a higher relative density than 98.0% with closed pores nevertheless capsule-free HIPing. Distribution of Mo2N particles just formed suppressed the grain growth of Al2O3 during sintering. Mechanical properties, such as bending strength (Σb), Vickers hardness (HV), fracture toughness (K1C), and other properties have been evaluated as a function of their compositions. The best mechanical values of Σb (c.a. 573 MPa), HV (c.a. 20.3 GPa) and K1C (c.a. 5.00 MPa･m1/2) were attained at the composition of Al2O3/Mo2N=90/10 vol%, due to a high density (98.6%) and small grain size of Al2O3 matrix (Gs c.a. 4.70 μm). Further addition of Mo2N reduced the sinterability of matrix grains, resulting in low densities of around 90% at the 40/60 vol% composition.

The Influence of Zirconia Powder Dispersion Technique on Microstructure and Properties of Al2O3 – ZrO2 Ceramic

2014 ◽  
Vol 682 ◽  
pp. 109-112
Author(s):  
Sergey Veselov ◽  
N.Yu. Cherkasova ◽  
R.S. Timarevskiy
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Size ◽  
Bending Strength ◽  
Preliminary Treatment ◽  
Zirconia Powder ◽  
Powder Dispersion ◽  
Dispersion Technique ◽  
Zirconia Toughened Alumina ◽  
Zirconia Suspension

The results of microstructure and mechanical properties investigation for alumina and zirconia toughened alumina (ZTA) with 20 wt. % 3Y-ZrO2is presented. It was stated that the technique of preliminary treatment for zirconia suspension makes significant influence on sintered specimen microstructure. Introduction of the alloying additive treated with ball milling reduces Al2O3grain size in ceramic from 2-5 μm to 0.2-1 μm. The reduction of grain size increases the bending strength of ceramic material from 270 MPa up to 350 MPa. However fracture toughness of alumina and ZTA is 3.4 and 2.5 MPa·m1/2, respectively. It was shown that the low level of mechanical properties is related to the occurrence of major defects in the form of granule boundaries preserved at the forming stage.

Mechanical Properties and Microstructure of Al2O3-TiC Composite by Hot-Pressing

2007 ◽  
Vol 336-338 ◽  
pp. 1424-1425
Author(s):  
Sui Lin Shi ◽  
Ling Zhen Zhang
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Scanning Electron Microscopy ◽  
Hot Pressing ◽  
Composite Powder ◽  
Bending Strength ◽  
Temperature Synthesis ◽  
High Temperature Synthesis ◽  
Scanning Electron

In this study, Al2O3-TiC composite was prepared at 1600°C for 1 h by hot-pressing using the Al2O3-TiC composite powder synthesized from self-propagating high-temperature synthesis (SHS) process. Mechanical properties of the composite were investigated, such as bulk density, Vickers hardness, fracture toughness and bending strength. The microstructure of the composite was also investigated by scanning electron microscopy (SEM).

Mechanical Properties of (Al2O3+Ni) and (Al2O3+Ni)/Ni Laminated Materials

2007 ◽  
Vol 353-358 ◽  
pp. 1447-1450
Author(s):  
Kai Hui Zuo ◽  
Dong Liang Jiang ◽  
Qing Ling Lin ◽  
Yu Ping Zeng ◽  
Zhong Ming Chen
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Size ◽  
Hot Pressing ◽  
Tape Casting ◽  
Crack Deflection ◽  
Second Phase ◽  
Microstructure Refinement ◽  
Hot Pressing Sintering ◽  
Laminated Materials

(Al2O3+Ni) and (Al2O3+Ni)/Ni laminated materials were prepared by tape casting and hot pressing sintering. The mechanical properties of (Al2O3+20wt%Ni) laminated composites were higher than those of (Al2O3+50wt%Ni) composites and Al2O3 sample. The strengthening in the (Al2O3+Ni) composites mainly results from microstructure refinement of the alumina grain size, cracks bridging and crack deflection by the Ni particles. Results showed that the strength and fracture toughness of (Al2O3+Ni)/Ni laminated materials were higher than those of Al2O3/Ni laminated materials with the same layer numbers and thickness ratio. The good mechanical properties of (Al2O3+Ni) and (Al2O3+Ni)/Ni laminated materials result from the second phase of Ni particles in Al2O3 layers.

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