Property and Microstructure of Machinable B4C/BN Nanocomposites

2008 ◽  
Vol 368-372 ◽  
pp. 936-939 ◽  
Author(s):  
Tao Jiang ◽  
Zhi Hao Jin ◽  
Jian Feng Yang ◽  
Guan Jun Qiao
Keyword(s):  
Fracture Toughness ◽  
High Temperature ◽  
Chemical Reaction ◽  
Fracture Strength ◽  
Vickers Hardness ◽  
Hot Pressing ◽  
Composite Powders ◽  
B4c Particles ◽  
Hot Pressing Sintering ◽  
Nanocomposite Powders

The B4C/BN nanocomposites were fabricated by hot-pressing sintering of the B4C/BN nanocomposite powders at 1850oC for 1h under the pressure of 30MPa. The composite powders with the microstructure of B4C particles coated with nano-sized BN particles were prepared by the chemical reaction of H3BO3 and CO(NH2)2 on the surface of B4C particles at high temperature. The microstructure investigation of the nanocomposites sintered samples showed that the nano-sized h-BN particles were homogenously distributed in the B4C matrix. With the increasing content of h-BN, the density of the B4C/BN nanocomposites decreased gradually; the fracture strength and fracture toughness of the B4C/BN nanocomposites decreased gradually, the strength and toughness of the B4C/BN nanocomposites with the h-BN content of 10wt% and 20wt% achieved high values. The Vickers hardness of the B4C/BN nanocomposites decreased remarkably with the increasing content of h-BN, while the machinability of the B4C/BN nanocomposites was significantly improved. The B4C/BN nanocomposites with the h-BN content more than 20wt% exhibited excellent machinability.

Investigation of Phase Composition and Microstructure of the B4C/BN Nanocomposite Powders and the B4C/BN Nanocomposites Sintered Bulks

2011 ◽  
Vol 328-330 ◽  
pp. 1572-1575
Author(s):  
Tao Jiang
Keyword(s):  
Heat Treatment ◽  
Phase Composition ◽  
Chemical Reaction ◽  
Hot Pressing ◽  
Treatment Process ◽  
Heat Treatment Process ◽  
Composite Powders ◽  
Pressing Process ◽  
Xrd Patterns ◽  
Nanocomposite Powders

In this research, the B4C/BN nanocomposite powders were fabricated by chemical reaction and heat treatment process, then the B4C/BN nanocomposites bulks were fabricated by hot-pressing process. The B4C/BN nanocomposite powders were fabricated by chemical reaction at 550°C for 15h and heat treatment at 850°C for 6h. The B4C/BN nanocomposites bulks were fabricated by hot-pressing process at 1850°C for 1h under the pressure of 30MPa. In this research, the phase composition and microstructure of the B4C/BN nanocomposite powders produced by chemical reaction and heat treatment process were investigated. The phase composition and microstructure of the B4C/BN nanocomposites produced by hot-pressing process were investigated. The XRD patterns results showed that there existed the B4C phase and amorphous BN phase in the composite powders produced by chemical reaction and heat treatment, and the amorphous BN phase completely transformed into the h-BN phase by hot-pressing process. The XRD patterns results showed that there existed the B4C phase and h-BN phase in the composites sintered bulks. The microstructure of the synthesized B4C/BN composite powders showed that the B4C particles were surrounded with the amorphous BN nano-sized particles, the thickness of amorphous BN coated layer was about 300-500nm. The B4C/BN nanocomposites exhibited the homogenous and compact microstructure, and the nano-sized h-BN particles were homogenously distributed in the B4C matrix. The mean particles size of B4C matrix was about 2-3μm, the length of nano-sized h-BN particles was about 1-2μm and width of nano-sized h-BN particles was about 100-200nm. The B4C/BN nanocomposites bulks exhibited more homogenous and compact microstructure with the increase of h-BN content.

Microstructure and Mechanical Properties of TiC/Ti3AlC2 In Situ Composites Prepared by Hot Pressing Method

2015 ◽  
Vol 816 ◽  
pp. 200-204 ◽  
Author(s):  
Miao Miao Ruan ◽  
Xiao Ming Feng ◽  
Tao Tao Ai ◽  
Ning Yu ◽  
Kui Hua
Keyword(s):  
Fracture Toughness ◽  
Flexural Strength ◽  
Vickers Hardness ◽  
Hot Pressing ◽  
Sintering Temperature ◽  
Powder Mixtures ◽  
Pressing Method ◽  
Hot Pressing Sintering ◽  
Sintering Method

TiC/Ti3AlC2 composites were successfully prepared by hot-pressing sintering method from the elemental powder mixtures of Ti, Al and TiC. A possible reaction mechanism was investigated by XRD. The density, Vickers hardness, flexural strength, and fracture toughness of the TiC/Ti3AlC2 composites were also measured. At 660 °C, Al melted and reacted with Ti to form TiAl3. At 900 °C, TiAl3 reacted with TiC and Ti to form Ti2AlC. At 1100 °C, Ti2AlC reacted with TiC to form Ti3AlC2. Increasing the sintering temperature, the content of Ti3AlC2 increased. The TiC/Ti3AlC2 composites had excellent performance after sintered at 1100 °C, the density, Vickers hardness, flexural strength and fracture toughness of the composite were 4.35 g/cm3, 4.72 GPa, 566 MPa and 6.18 MPa·m1/2, respectively.

Fabrication of the Composite Ceramic Material ACS

2011 ◽  
Vol 365 ◽  
pp. 135-139
Author(s):  
De Ming Sun ◽  
Chong Hai Xu ◽  
Liu Bo Yang ◽  
Jing Li
Keyword(s):  
Fracture Toughness ◽  
Flexural Strength ◽  
Ceramic Material ◽  
Chemical Reaction ◽  
Hot Pressing ◽  
Composite Ceramic ◽  
Chemical Compatibility ◽  
Al2o3 Ceramic ◽  
Hot Pressing Sintering ◽  
Composite Ceramic Material

Based on the theory of thermodynamics, the chemical compatibility of the possible composition system of ceramic material Al2O3/Cr3C2/SiC (for short ACS) was analyzed. The results show that no chemical reaction could take place under 1800°C through Cr3C2, SiC and Al2O3. And it was tested by the fabrication of the Al2O3/Cr3C2/SiC composite with the hot pressing sintering technique. The flexural strength and fracture toughness of ACS are super than the Al2O3 ceramic.

Effect of Co Content on the Densification, Microstructure and Mechanical Properties of cBN-WC/Co Composites

2015 ◽  
Vol 655 ◽  
pp. 41-44
Author(s):  
Qiu Shuang He ◽  
Hai Yan Chen ◽  
Kun Li ◽  
Li Hua Dong
Keyword(s):  
Mechanical Properties ◽  
Vickers Hardness ◽  
Hot Pressing ◽  
Cemented Carbide ◽  
Sintering Process ◽  
Composite Powders ◽  
Flexure Strength ◽  
Microstructure And Mechanical Properties ◽  
Hot Pressing Sintering ◽  
Full Densification

Hot pressing sintering process for cemented carbide preparation was investigated with cBN-WC/Co composite powders with different Co content from 4wt% to 10wt% at temperatures between 1300°C and 1400°C. The results showed that the Co content had remarkable influence on the densification and mechanical properties of cBN-WC/Co composites. Near-full densification can be obtained when cBN-WC/8wt%Co powders were sintered at temperatures at 1350°C, and pressures at 20MPa, combining an excellent Vickers hardness of 17.57GPa with an acceptable flexure strength of 601.58MPa.

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.

Effect of BN Short Fiber Content on Mechanical Properties of ZrB2-SiC UHTCs

2012 ◽  
Vol 512-515 ◽  
pp. 706-709 ◽  
Author(s):  
Chang Ling Zhou ◽  
Yan Yan Wang ◽  
Zhi Qiang Cheng ◽  
Chong Hai Wang ◽  
Rui Xiang Liu
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Scanning Electron Microscopy ◽  
Flexural Strength ◽  
Hot Pressing ◽  
Ceramic Composites ◽  
Short Fiber ◽  
Hot Pressing Sintering ◽  
Scanning Electron

ZrB2-20%volSiC ceramic composites with different volume of BN short fiber were fabricated by the hot-pressing sintering under 2000°C. The content of BN short fiber changed from 0 to 15vol%. The density, flexural strength, fracture toughness and thermal expansions coefficient were studied. The microstructures of the samples were observed by scanning electron microscopy. The results show that the introducing of BN short fiber into the ZrB2-20%volSiC lead to a serious of change to the mechanical properties of the ceramic. When the content of the BN short fiber is 10vol%, the flexural strength and fracture toughness reach 422.1MPa and 6.15 MPa•m 1/2 respectively. And the mechanism of the increasing toughness was studied.

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.

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.

Microstructure and Properties of Hot-Pressing Sintered Tungsten Carbide Composites by Adding Cubic Boron Nitride

2015 ◽  
Vol 655 ◽  
pp. 45-48
Author(s):  
Kun Li ◽  
Hai Yan Chen ◽  
Qiu Shuang He ◽  
Li Hua Dong
Keyword(s):  
Mechanical Properties ◽  
Boron Nitride ◽  
Flexural Strength ◽  
Tungsten Carbide ◽  
Vickers Hardness ◽  
Hot Pressing ◽  
Cubic Boron Nitride ◽  
Microstructure And Mechanical Properties ◽  
Hot Pressing Sintering ◽  
Sintering Method

(0, 5, 10, 15, 20) vol% CBN-WC/Co composites were consolidated by ball milling and the following hot-pressing sintering method. WC, Co and CBN powders were used as the starting materials. The effects of the CBN content on the density, microstructure and mechanical properties of CBN-WC/Co composites were investigated. The results showed that the CBN content had remarkable influence on the microstructure and mechanical properties of CBN-WC/Co Composites. With the increasing content of CBN, the density decrease, while Vickers hardness and flexural strength increased initially to the maximum values and then decreased at CBN 10 vol%. When 10 vol% CBN-WC/Co powders were hot-pressing sintered at 1350°C and 20MPa for 90 min, an excellent Vickers hardness of 19.8GPa was achieved, combining a flexural strength of 682MPa.

Fabrication and Mechanical Properties of SiC/Cu Composites with Zn Addition by Hot Pressing Sintering

2013 ◽  
Vol 745-746 ◽  
pp. 700-705
Author(s):  
Huang Liu ◽  
Guo Qiang Luo ◽  
Pin Gan Chen ◽  
Qiang Shen ◽  
Lian Meng Zhang
Keyword(s):  
Mechanical Properties ◽  
Vickers Hardness ◽  
Hot Pressing ◽  
Bending Strength ◽  
Coefficient Of Thermal Expansion ◽  
High Volume ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zn Addition ◽  
Hot Pressing Sintering

SiC/Cu composites exhibit low density, low coefficient of thermal expansion and excellent mechanical properties. In this study, Zn of 2 wt. % was added as the sintering activator, and the high volume faction (60%) SiC/Cu composites was fabricated by hot pressing sintering technology. The phase composition and morphology of as-prepare samples were characterized by X-ray diffraction (XRD) system and scanning electron microscopy (SEM) equipped with an energy-dispersive spectroscopy (EDS) system. The as-prepared SiC/Cu composites were dense and uniform as well as void free. The results show that SiC/Cu composites can reach excellent mechanical properties of SiC/Cu composites. With the increase of sintering temperature, Vickers hardness and the bending strength of the samples increased obviously and the as-prepared SiC/Cu composites achieved a maximum Vickers hardness and bending strength respectively of 195MPa and 140MPa.

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