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).

Effects of Rapid Heat Treatment on Microstructure and Mechanical Properties of Ti2AlC/TiAl Composite

2007 ◽  
Vol 336-338 ◽  
pp. 1164-1167
Author(s):  
Yun Long Yue ◽  
Hai Tao Wu ◽  
Wei Bing Wu ◽  
Hai Yan Yin
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Fracture Toughness ◽  
Bending Strength ◽  
Duplex Microstructure ◽  
Microstructure And Mechanical Properties ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Rapid Heat Treatment

In this paper Ti2AlC/TiAl composites were in-situ fabricated by spark plasma sintering (SPS) and then the effects of rapid heat-treatment on microstructure and mechanical properties of Ti2AlC/TiAl composites were investigated. After rapid heat-treatment the microstructure of TiAl matrix was significantly transformed from the near γ microstructure to duplex microstructure. Ti2AlC particles effectively refined the γ phase grains and the α2/γ lamellar colony microstructure. For the Ti2AlC/TiAl composite after rapid heat-treatment at 1200°C, the bending strength and fracture toughness reached 956.8MPa and 22.8MPa·m1/2, respectively.

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 Nano-Al2O3 on the Microstructure and Properties of ZrO2 Dental Materials Prepared by Microwave Sintering

2014 ◽  
Vol 618 ◽  
pp. 3-7 ◽  
Author(s):  
Yun Long Ai ◽  
Xiang Hua Xie ◽  
Wen He ◽  
Bing Liang Liang ◽  
Wei Hua Chen
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Bending Strength ◽  
Microwave Sintering ◽  
Dental Materials ◽  
Transgranular Fracture ◽  
Composite Ceramics ◽  
Obvious Effect ◽  
Size Uniformity ◽  
Mutual Relations

Al2O3(x)/ZrO2composite ceramics were successfully prepared by microwave sintering. The influence of variety content of nanoAl2O3on mechanical properties and microstructure of ZrO2dental materials were studied, and analysied the mutual relations of chemical composition, mechanical properties and microstructure to investigate the reason of strengthening and toughening. Results indicated that The relative density of the Al2O3(x)/ZrO2composite ceramics reached more than 96.8%.The HV hardness ,bending strength and fracture toughness presented excellent mechanical properties as 12.5GPa, 753.8MPa and 11.8MPa·m1/2with the content of nanoAl2O3was 7.5%. Compared with that of pure ZrO2ceramics, the bending strength and the fracture toughness were improved 19% and 96%, respectively. The main crystal phases in this composite ceramics were t-ZrO2and α-Al2O3.The nanoAl2O3have a obvious effect on the strength and toughness of ZrO2based ceramics. The reason of strengthening and toughening mainly the additions reduced the ZrO2grains growth and promoted grains size uniformity, and changed the fracture mode from transgranular fracture to intergranular fracture characteristics.

Effect of La2O3 Addition on the Microstructure and Mechanical Properties of TiC-Based Cermets

2014 ◽  
Vol 633-634 ◽  
pp. 355-359
Author(s):  
Jia Xie ◽  
De Kai Li ◽  
Lian Chao Wang ◽  
Yun Xi
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Bending Strength ◽  
Undoped Sample ◽  
Vacuum Sintering ◽  
Moderate Amount ◽  
Comprehensive Properties ◽  
Eds Analysis ◽  
Microstructure And Mechanical Properties ◽  
New Phase

TiC-based cermets with four different components of La2O3 content were prepared via vacuum sintering to investigate the effect of La2O3 addition on the microstructure and mechanical properties. The microstructure and phase structure were investigated by XRD, SEM, EDS and the mechanical properties were measured. Experimental results show that TiC-based cermets with La2O3 addition were also a typical core-rim structure but did not form a new phase. Along with the increase of La2O3 content, the density of TiC-based cermets was reduced, EDS analysis revealed La2O3 was partly dissolved in the Mo/Ni binder and hindered dissolution and separation of carbides. A moderate amount of La2O3 can favor the microstructure refinement and improve its mechanical properties in the form of La2O3 particles embedded in Mo/Ni particles. Compared with undoped sample, the cermets doped with 1 wt.% La2O3 showed optimum comprehensive properties: the bending strength of 1041.4 MPa, Vickers hardness of 13.19 GPa and the fracture toughness of 14.18 MPa• m1/2.

Effect of TiC Content on the Microstructure and Mechanical Properties of Ti3AlC2/Al2O3 In Situ Composites Synthesized by Hot Pressing

2012 ◽  
Vol 724 ◽  
pp. 278-281 ◽  
Author(s):  
Lan Ye ◽  
Jian Feng Zhu
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Phase Composition ◽  
Flexural Strength ◽  
High Temperatures ◽  
Vickers Hardness ◽  
Hot Pressing ◽  
Microstructure And Mechanical Properties ◽  
Reactive Hot Pressing

The Ti3AlC2/Al2O3 in situ composites were successfully synthesized from the system of Ti-TiC-Al-TiO2 by reactive hot pressing at 1350 °C. The effect of TiC content on the phase composition, microstructure and mechanical properties were investigated in detail. The results indicate that the fabricated products possess the highest purity as the TiC contents reduce to 90 % of its theoretical content. This deviation is mainly attributed to the decomposition of Ti3AlC2 and vaporization of Al at high temperatures. The effect of TiC content on the fracture toughness, flexural strength, Vickers hardness of Ti3AlC2/Al2O3 composites was also discussed in detail.

Effects of Calcium Hexaluminate Addition on the Mechanical Properties of Zirconia-Toughened-Alumina

2013 ◽  
Vol 544 ◽  
pp. 286-290 ◽  
Author(s):  
Mei Ling Hu ◽  
Ming Hao Fang ◽  
Shu Sen Chen ◽  
Tao Yang ◽  
Zhao Hui Huang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Bending Strength ◽  
Alumina Ceramic ◽  
Pressureless Sintering ◽  
Composite Ceramics ◽  
Microstructure And Mechanical Properties ◽  
Calcium Hexaluminate ◽  
Zirconia Toughened Alumina

The effects of calcium hexaluminate addition on the microstructure and mechanical properties of zirconia-toughened-alumina ceramic were investigated. Zirconia-toughened-alumina (ZTA) composite ceramics which have different additions of calcium hexaluminate were successfully fabricated by pressureless sintering at 1600°C for 3h. The result shows that the bending strength and abrasive wearing improved with the increasing of CaAl12O19addition while the fracture toughness declined.

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.

In Situ Preparation and Mechanical Properties of (ZrB2+ZrC)/Zr3[Al(Si)]4C6 Composites

2014 ◽  
Vol 602-603 ◽  
pp. 438-442
Author(s):  
Lei Yu ◽  
Jian Yang ◽  
Tai Qiu
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Bending Strength ◽  
Coefficient Of Thermal Expansion ◽  
Raw Materials ◽  
Linear Increase ◽  
Fine Grain ◽  
Fine Grain Strengthening ◽  
Uniform Microstructure

Fully dense (ZrB2+ZrC)/Zr3[Al (Si)]4C6 composites with ZrB2 content varying from 0 to 15 vol.% and fixed ZrC content of 10 vol.% were successfully prepared by in situ hot-pressing in Ar atmosphere using ZrH2, Al, Si, C and B4C as raw materials. With the increase of ZrB2 content, both the bending strength and fracture toughness of the composites increase and then decrease. The synergistic action of ZrB2 and ZrC as reinforcements shows significant strengthening and toughing effect to the Zr3[Al (Si)]4C6 matrix. The composite with 10 vol.% ZrB2 shows the optimal mechanical properties: 516 MPa for bending strength and 6.52 MPa·m1/2 for fracture toughness. With the increase of ZrB2 content, the Vickers hardness of the composites shows a near-linear increase from 15.3 GPa to 16.7 GPa. The strengthening and toughening effect can be ascribed to the unique mechanical properties of ZrB2 and ZrC reinforcements, the differences in coefficient of thermal expansion and modulus between them and Zr3[Al (Si)]4C6 matrix, fine grain strengthening and uniform microstructure derived by the in situ synthesis reaction.

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.

Synthesis of Al2O3/AlB12/Al Composite Ceramic Powders by Pulsed Nd:YAG Laser Igniting Method and a Study of their Mechanical Properties

2010 ◽  
Vol 26-28 ◽  
pp. 919-924
Author(s):  
Kai Jin Huang
Keyword(s):  
Fracture Toughness ◽  
Reaction Mechanism ◽  
Nd:Yag Laser ◽  
Bending Strength ◽  
Composite Ceramic ◽  
Composite Ceramics ◽  
Ceramic Powders ◽  
Pulsed Nd:Yag Laser ◽  
Al Composite ◽  
Pure Al2o3

Based on the combined toughening principle, pure Al2O3/AlB12/Al composite ceramic powders have been synthesized using pulsed Nd:YAG laser igniting method. This method starts from Al and B2O3 powder mixtures, after which Al2O3/AlB12/AlN composite ceramics were fabricated by hot-press sintering at 1600°C for 2h under the protection of a N2 atmosphere. XRD and SEM techniques were used to characterize the phases and morphologies of the powders and the ceramics. The bending strength and the fracture toughness of the ceramics were measured by the three-point bending method and the indentation fracture method, respectively. The results show that the pure Al2O3/AlB12/Al composite ceramic powders can be successfully synthesized by pulsed Nd:YAG laser igniting method because the adiabatic temperature of Al-B2O3 system is more than 1800K. Al2O3 and AlB12 phases were formed by the liquid-liquid reaction mechanism and the liquid-solid reaction mechanism, respectively. The bending strength and the fracture toughness of the Al2O3/AlB12/AlN composite ceramics were 525.86MPa and 5.68MPa.m1/2, respectively. These values are 50.25% and 42% greater than those of the pure Al2O3 ceramic (350MPa and 4MPa.m1/2) due to the reinforcing and toughening in-situ formation of small AlN particles.

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