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.

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.

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.

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).

ZrO2-TiN Composites

2007 ◽  
Vol 554 ◽  
pp. 135-140 ◽  
Author(s):  
Sedigheh Salehi ◽  
Omer Vander Biest ◽  
Jef Vleugels
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Vickers Hardness ◽  
Hot Pressing ◽  
Bending Strength ◽  
Transformation Toughening ◽  
Toughening Mechanism ◽  
Indentation Toughness ◽  
Tin Content ◽  
Composite Toughness

1.75 mol % Y2O3-stabilized ZrO2-based composites with 35-95 vol % TiN were fully densified by hot pressing for 1 hour at 1550°C under a load of 28 MPa. The TiN grain size was found to increase with increasing TiN content, resulting in a decreasing hardness and strength. The best mechanical properties, i.e., an indentation toughness of 5.9 MPa.m1/2 in combination with a Vickers hardness of 14.7 GPa and an excellent bending strength of 1674 MPa were obtained for the composites with 40 vol % TiN. The active toughening mechanisms were identified and their contribution to the overall composite toughness is discussed. Transformation toughening was found to be the primary toughening mechanism in all investigated composites.

The Mechanical Properties of AlN/BN Laminated Ceramic Composites

2008 ◽  
Vol 569 ◽  
pp. 97-100 ◽  
Author(s):  
Tao Zhang ◽  
Hai Yun Jin ◽  
Yong Ian Wang ◽  
Zhi Hao Jin
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Hot Pressing ◽  
Bending Strength ◽  
Tape Casting ◽  
Ceramic Composites ◽  
Crack Deflection ◽  
Weak Interface ◽  
Parallel Propagation ◽  
Monolithic Ceramics

AlN/BN laminated ceramic composites were fabricated using tape-casting and hot-pressing by optimizing the designs of the structure and geometry of AlN/BN laminated ceramic composites. The results showed that the fracture toughness and bending strength for AlN/BN laminated ceramics reached 9.1MPa.m1/2 and 378MPa respectively. The fracture toughness is two times higher than that of AlN monolithic ceramics. The excellent fracture toughness of AlN/BN laminated ceramics could be mainly attributed to crack deflection, delaminating, branching, parallel propagation and crack laminate pilling out at the AlN/BN weak interface.

Effect of Holding Time on Microstructure and Properties of VC/Fe Composite

2012 ◽  
Vol 723 ◽  
pp. 353-357
Author(s):  
Guo Jun Zhang ◽  
Zhi Ping Sun ◽  
Li Yan Zou
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Relative Density ◽  
Bending Strength ◽  
Holding Time ◽  
Microstructure And Properties ◽  
Microstructure And Mechanical Properties ◽  
Relationship Of ◽  
The Relationship ◽  
Better Than

The microstructure and mechanical properties of samples were examined, and the relationship of structure and mechanical properties for VC/Fe composite sintered at different holding time were studied. Holding time can influence the mechanical properties, with the holding time rising, when the holding time is 80 min, the hardness is Max, it’s 10.71 GPa, the enhancing range is 37.66%; The relative density changes slower from 60 to 100 min; when the holding time is 60 minutes, fracture toughness and bending strength of material is 16.17 MPa•m 1/2 and 1070 MPa, it’s better than before.

Study on ZrC-20vol.%SiCw Ultrahigh Temperature Ceramics by Hot Pressing

2012 ◽  
Vol 557-559 ◽  
pp. 772-775 ◽  
Author(s):  
Jin Ping Li ◽  
Song He Meng ◽  
Zhi Bo Wang ◽  
Qing Liu ◽  
Yu Min Zhang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Hot Pressing ◽  
Sem Analysis ◽  
Toughening Mechanism ◽  
Fine Grain ◽  
Fine Grain Strengthening ◽  
Pull Out ◽  
Sic Whiskers ◽  
Ultrahigh Temperature

The ZrC-20vol.%SiCw ultrahigh temperature ceramics with relative density of 99.2% can be prepared by hot pressing at 1900 oC and 30MPa for 60 min. The mechanical properties and microstructure of the composite were studied. The flexural strength and fracture toughness reaches up to 626.17MPa, 5.03 MPa•m1/2, respectively. SEM analysis shows the microstructure of the ZrC-20vol.%SiCw is homogeneous and SiC whiskers are uniformly distributed around the ZrC grains, which inhibit the ZrC grain growth during sintering. The fracture surface of ZrC-20vol.%SiCw reveals a mixture of intergranular and transgranular failure, and SiC whiskers play a remarkable role in improving the strength and toughness of ZrC matrix. The toughening mechanism of the composite is mainly fine-grain strengthening and whisker pull-out.

Study on Mechanical Properties and Toughening Mechanism of MWCNTs/Ti(C, N) Cermets-Based Composites

2013 ◽  
Vol 544 ◽  
pp. 291-294
Author(s):  
Shuo Qi Liu ◽  
Wei Liang Liu
Keyword(s):  
Crystal Structure ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Residual Stress ◽  
Vickers Hardness ◽  
Bending Strength ◽  
Crack Deflection ◽  
Toughening Mechanism ◽  
Hot Pressing Sintering ◽  
Sintering Method

MWCNTs/Ti(C, N) cermets-based composites were prepared by vacuum hot-pressing sintering method. The mechanical properties of samples were examined. XRD and SEM were used to investigate the crystal structure of the composites and microstructure of fractures surface, respectively. The toughening mechanism of composites was discussed particularly. The experimental results showed that the optimum comprehensive mechanical properties of samples were obtained by adding 1wt% MWCNTs in the composites. The bending strength, Vickers hardness and fracture toughness of the composites were 1275.14MPa, 22.75GPa and 10.60MPa•m1/2, respectively, which were improved by 16.89%, 17.15% and 25.59%, respectively, compared to the Ti(C, N)-based cermets without MWCNTs. Bridging and pulling out of MWCNTs, crack deflection, residual stress toughening and micro-voids toughening were attributed to the toughening mechanism of the composites.

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.

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