Microstructure and Mechanical Properties of In Situ Al2O3- Ti(C,N) Composites

2011 ◽  
Vol 239-242 ◽  
pp. 1243-1247
Author(s):  
Xiu Mei Feng ◽  
Xiao Qing Lian ◽  
Ming Xue Jiang ◽  
Yi Ner He
Keyword(s):  
Mechanical Properties ◽  
Bulk Density ◽  
Raw Materials ◽  
In Situ Synthesis ◽  
Apparent Porosity ◽  
Composite Ceramics ◽  
Comprehensive Properties ◽  
Microstructure And Mechanical Properties ◽  
Metal Aluminum

Al2O3-Ti(C,N)composite ceramics were prepared by in situ aluminothermic reduction and pressureless sintering. The effects of different Ti(C,N) contents and sintering temperatures on microstructure and mechanical properties (bulk density ,apparent porosity and blending strength)of samples were investigated through experiments.The results show that Al2O3-Ti(C,N) composite ceramics with 10 wt.% Ti(C,N) prepared using titanium dioxide and metal aluminum powder as raw materials and sintered at 1300 °C for 3h under a flowing nitrigen stream have good properties ,with bulk density 2.94g/cm3,apparent porosity 26.4%, and blending strength reaches to 28.04 MPa. According to the microstructure analysis,the fine in situ synthesis Ti(C,N) particles are uniformly dispersed in tabular alundum matrix. Ti(C,N) and tabular alundum phases are closely combined and can inhibit grain growth each other,which is benefical in improving the comprehensive properties of composite ceramics.

Effect of Z Values on the Microstructure and Mechanical Properties of Post-sintered Reaction Bonded β-SiAlON

2017 ◽  
Vol 36 (5) ◽  
pp. 453-458 ◽  
Author(s):  
Yanjun Li ◽  
Donghua Liu ◽  
Han Jin ◽  
Donghai Ding ◽  
Guoqing Xiao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Phase Composition ◽  
Bulk Density ◽  
Grain Growth ◽  
Bending Strength ◽  
Raw Materials ◽  
Apparent Porosity ◽  
Reaction Bonding ◽  
Microstructure And Mechanical Properties ◽  
Before And After

Abstractβ-SiAlON materials with different Z values (Z=0.5–3) were fabricated by a reaction bonding combining post-sintering route using raw materials of Si, Al2O3, AlN, etc. The reaction bonded β-SiAlON (RB-β-SiAlON) were post-sintered at 1,750 °C for 6 h. Apparent porosity, bulk density, bending strength and Vicker’s hardness of the samples before and after post-sintering were tested. XRD results showed that the phase composition of both RB-β-SiAlON and post-sintered RB-β-SiAlON (PSRB-β-SiAlON) were β-SiAlON. For RB-β-SiAlON, the apparent porosity was decreased with the increase of Z values, while the strength and hardness was increased accordingly. After the post-sintering procedure, nearly full densified PSRB-β-SiAlON was obtained and the mechanical properties were significantly improved. The bending strength and Vicker’s hardness of the PSRB-β-SiAlON (Z=0.5) achieved 510 MPa and 16.5 GPa, respectively, which were as 2.7 and 6.7 times high as those of the corresponding RB-β-SiAlON. However, the strength and hardness of PSRB-β-SiAlON decreased with the increase of Z value due to the grain growth.

Effects of Nb2O5/La2O3 Synergistic Modification on Phase Composition, Microstructure and Mechanical Properties of Al2O3 Ceramics Prepared by Microwave Sintering

2014 ◽  
Vol 633 ◽  
pp. 49-52
Author(s):  
Yun Long Ai ◽  
Kai Wu ◽  
Xiang Hua Xie ◽  
Bing Liang Liang ◽  
Wen He ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Phase Composition ◽  
Bending Strength ◽  
Microwave Sintering ◽  
Composite Ceramic ◽  
Composite Ceramics ◽  
Comprehensive Properties ◽  
Microstructure And Mechanical Properties

Nb2O5-7.5La2O3-Al2O3 composite ceramics were prepared by microwave sintering. The influence of Nb2O5 and La2O3 proportion on the microstructure and mechanical properties of Al2O3 ceramics was investigated. The results show that when the Nb2O5 content was lower than La2O3, the columnar LaAl11O18 grains were generated by the reaction of La2O3 with Al2O3. When the Nb2O5 content was higher than La2O3, the surplus Nb2O5 induced the formation of columnar Al2O3 grains. The growth of columnar Al2O3 grains were promoted synergistically by LaNbO4 formed in-situ and Nb2O5. The 5Nb2O5-7.5La2O3-Al2O3 composite ceramic exhibited excellent comprehensive properties: ρr=99.3% (relative density), HV=11.2GPa (microhardness), KIC= 6.4MPa·m1/2 (fracture toughness), σ=304.3MPa (bending strength).

scholarly journals Effect of Sintering Temperature on Microstructure and Mechanical Properties of Hot-Pressed Fe/FeAl2O4 Composite

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 422
Author(s):  
Kuai Zhang ◽  
Yungang Li ◽  
Hongyan Yan ◽  
Chuang Wang ◽  
Hui Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Hot Press ◽  
Microstructure And Mechanical Properties ◽  
Powder Particles ◽  
Hot Press Sintering ◽  
Sintering Method

An Fe/FeAl2O4 composite was prepared with Fe-Fe2O3-Al2O3 powder by a hot press sintering method. The mass ratio was 6:1:2, sintering pressure was 30 MPa, and holding time was 120 min. The raw materials for the powder particles were respectively 1 µm (Fe), 0.5 µm (Fe2O3), and 1 µm (Al2O3) in diameter. The effect of sintering temperature on the microstructure and mechanical properties of Fe/FeAl2O4 composite was studied. The results showed that Fe/FeAl2O4 composite was formed by in situ reaction at 1300 °C–1500 °C. With the increased sintering temperature, the microstructure and mechanical properties of the Fe/FeAl2O4 composite showed a change law that initially became better and then became worse. The best microstructure and optimal mechanical properties were obtained at 1400 °C. At this temperature, the grain size of Fe and FeAl2O4 phases in Fe/FeAl2O4 composite was uniform, the relative density was 96.7%, and the Vickers hardness and bending strength were 1.88 GPa and 280.0 MPa, respectively. The wettability between Fe and FeAl2O4 was enhanced with increased sintering temperature. And then the densification process was accelerated. Finally, the microstructure and mechanical properties of the Fe/FeAl2O4 composite were improved.

Effect of VC Addition on Microstructure and Mechanical Properties of Ultrafine Grained WC-Co Alloys

2014 ◽  
Vol 893 ◽  
pp. 444-448 ◽  
Author(s):  
Xue Mei Liu ◽  
Xiao Yan Song ◽  
Hai Bin Wang ◽  
Yang Gao ◽  
Yao Wang
Keyword(s):  
Mechanical Properties ◽  
Composite Powder ◽  
Cemented Carbides ◽  
Comprehensive Properties ◽  
Microstructure And Mechanical Properties ◽  
Plasma Sintering ◽  
Ultrafine Grained ◽  
Spark Plasma ◽  
Co Alloys

This study was focused on the effect of VC addition on the microstructure and mechanical properties of the prepared ultrafine grained cemented carbides. VC was added to the rawoxide materials which were synthesized to the WC-Co composite powder by the in-situ reduction and carbonization process. The ultrafine grained WC-Co alloys were fabricated by the spark plasma sintering technique using the prepared WC-Co composite powder. The phase constitution, microstructure characteristics and mechanical properties of the sintered ultrafine grained cemented carbides were analyzed quantitatively. The study proposed that VC plays a significant role in decreaseing the grain size of the prepared WC-Co alloy. The ultrafine grained WC-Co alloy with high comprehensive properties can be obtained as an appropriate addition of VC in the developed process.

scholarly journals Si3N4-SiCpComposites Reinforced byIn SituCo-Catalyzed Generated Si3N4Nanofibers

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Juntong Huang ◽  
Zhaohui Huang ◽  
Shaowei Zhang ◽  
Minghao Fang ◽  
Yan’gai Liu
Keyword(s):  
Mechanical Properties ◽  
Bulk Density ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Apparent Porosity ◽  
Network Connection ◽  
Opposite Trend ◽  
Low Sintering Temperature ◽  
Co Addition

Si3N4-SiCpcomposites reinforced byin situcatalytic formed nanofibers were prepared at a relatively low sintering temperature. The effects of catalyst Co on the phase compositions, microstructures, and physicochemical-mechanical properties of samples sintered at 1350°C–1450°C were investigated. The results showed that the catalyst Co enhanced the nitridation of Si. With the increase of Co addition (from 0 wt% to 2.0 wt.%), the apparent porosity of as-prepared refractories was initially decreased and subsequently increased, while the bulk density and the bending strength exhibited an opposite trend. TheSi3N4-SiCpcomposites sintered at 1400°C had the highest strength of 60.2 MPa when the Co content was 0.5 wt.%. The catalyst Co facilitated the sintering ofSi3N4-SiCpcomposites as well as the formation of Si3N4nanofibers which exhibited network connection and could improve their strength.

scholarly journals Microstructural evolution and mechanical properties of in situ nano Ta4HfC5 reinforced SiBCN composite ceramics

2020 ◽  
Vol 9 (6) ◽  
pp. 739-748
Author(s):  
Bingzhu Wang ◽  
Daxin Li ◽  
Zhihua Yang ◽  
Dechang Jia ◽  
Jingyi Guan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Microstructural Evolution ◽  
Hot Pressing ◽  
Raw Materials ◽  
Hybrid Structure ◽  
Second Step ◽  
Composite Ceramics ◽  
Hot Pressing Sintering ◽  
Reactive Hot Pressing

AbstractThe in situ nano Ta4HfC5 reinforced SiBCN-Ta4HfC5 composite ceramics were prepared by a combination of two-step mechanical alloying and reactive hot-pressing sintering. The microstructural evolution and mechanical properties of the resulting SiBCN-Ta4HfC5 were studied. After the first-step milling of 30 h, the raw materials of TaC and HfC underwent crushing, cold sintering, and short-range interdiffusion to finally obtain the high pure nano Ta4HfC5. A hybrid structure of amorphous SiBCN and nano Ta4HfC5 was obtained by adopting a second-step ball-milling. After reactive hot-pressing sintering, amorphous SiBCN has crystallized to 3C-SiC, 6H-SiC, and turbostratic BN(C) phases and Ta4HfC5 retained the form of the nanostructure. With the in situ generations of 2.5 wt% Ta4HfC5, Ta4HfC5 is preferentially distributed within the turbostratic BN(C); however, as Ta4HfC5 content further raised to 10 wt%, it mainly distributed in the grain-boundary of BN(C) and SiC. The introduction of Ta4HfC5 nanocrystals can effectively improve the flexural strength and fracture toughness of SiBCN ceramics, reaching to 344.1 MPa and 4.52 MPa·m1/2, respectively. This work has solved the problems of uneven distribution of ultra-high temperature phases in the ceramic matrix, which is beneficial to the real applications of SiBCN ceramics.

Mechanical Properties of Hot-Pressed B4C-TiB2 Composites Synthesized from B4C-TiO2 and B4C-TiC

2021 ◽  
Vol 902 ◽  
pp. 81-86
Author(s):  
Shu Mao Zhao ◽  
Ling Ran Zhao
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Volume Fraction ◽  
Raw Materials ◽  
Ceramic Composites ◽  
In Situ Synthesis ◽  
Second Phase ◽  
Pressing Method ◽  
The One

In this study, B4C-TiB2 ceramic composites were manufactured by hot pressing method. The raw materials for the in-situ synthesis of TiB2 were TiO2 and TiC. After being sintered at 1900°C for 60min under a pressure of 30MPa, compact composites samples with a TiB2 volume fraction range from 0 to 11.05% were prepared. The relative density, fracture toughness and flexural strength of different sample were tested. Microstructures on the fracture surface were studied by SEM. The result shows that B4C-TiB2 ceramic composites sintered from B4C-TiC had a better mechanical property than the one sintered from B4C-TiO2. When the content of TiB2 (reacted from TiC) was 11.05vol.%, the strength and toughness of B4C-TiB2 ceramics can reach 598MPa and 6.45MPa·m1/2. The toughening mechanisms of B4C-TiB2 composites include micro-crack toughening and energy consumption by the pulling out process of second phase.

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