Mechanical Properties of α- and β-SiAlON Composite Ceramics Using β-SiAlON Powder

2008 ◽  
Vol 403 ◽  
pp. 111-114 ◽  
Author(s):  
Kei Asakoshi ◽  
Junichi Tatami ◽  
Katsutoshi Komeya ◽  
Takeshi Meguro ◽  
Masahiro Yokouchi
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Rare Earth ◽  
Chemical Composition ◽  
Metal Oxides ◽  
Bending Strength ◽  
Rare Earth Oxide ◽  
Composite Ceramics ◽  
Oxide Powders ◽  
Sialon Powder

β-SiAlON powder was used as a raw powder to fabricate α/β-SiAlON composite ceramics with different rare earth elements. The phases present in the sample fabricated from -SiAlON, α-Si3N4, AlN, and rare earth oxide powders were - and -SiAlONs. The composition was dependent on the chemical composition and firing profile. The sample obtained by adding Yb2O3 had a high -SiAlON content. The /-SiAlON composite ceramics had high densit. Their microstructures depended on the used metal oxides, namely, the addition of Nd2O3 and CaCO3 resulted in the elongation of the -SiAlON grains. The bending strength, fracture toughness, and hardness were influenced by the -SiAlON content, amount of elongated grains, and density of the sample.

Effect of Rare Earth Oxide and Rare Earth-Alumina-Silica Glass on Mechanical Properties of Liquid Phase Sintered Alumina Ceramics

2005 ◽  
Vol 290 ◽  
pp. 246-249 ◽  
Author(s):  
Jaroslav Sedláček ◽  
Dušan Galusek ◽  
Pavol Šajgalík
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Rare Earth ◽  
Liquid Phase ◽  
Rare Earth Oxide ◽  
Aluminosilicate Glass ◽  
Alumina Ceramics ◽  
Beneficial Effects ◽  
Rare Earth Addition ◽  
The Impact

The microstructure evolution and mechanical properties of alumina doped with rare earth oxide and rare earth-aluminosilicate glass has been investigated in order to understand better the impact of rare earth addition on hardness and fracture toughness. The aims of the present work are to examine the possibly beneficial effects of selected rare earth oxide added to alumina by two different routes in enhancing mechanical properties. The specific systems considered in this work were as follows: liquid phase sintered alumina containing RE2O3 (RE = La, Y) and RE2O3 – Al2O3 – SiO2 glassy phase up to 5 wt. %. The Vickers hardness and fracture toughness have been compared with the undoped alumina.

scholarly journals Effect of Additive Ti3SiC2 Content on Mechanical Properties of B4C–TiB2 Composites Ceramics Sintered by Spark Plasma Sintering

2020 ◽  
Author(s):  
Xingheng Yan ◽  
Xingui Zhou ◽  
Honglei Wang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Spark Plasma Sintering ◽  
Bending Strength ◽  
High Fracture Toughness ◽  
Transgranular Fracture ◽  
Composite Ceramics ◽  
High Fracture ◽  
Plasma Sintering ◽  
Spark Plasma

Abstract B4C-TiB2 composite ceramics with ultra-high fracture toughness were successfully prepared via spark plasma sintering at 1900℃ using B4C and Ti3SiC2 as raw materials. The results show that compared with pure B4C ceramics sintered by SPS, the hardness of B4C-TiB2 composite ceramics is decreased, but the flexural strength and fracture toughness are significantly improved, especially the fracture toughness has been improved by leaps and bounds. When the content of Ti3SiC2 is 30vol.%, the B4C-TiB2 composite ceramic has the best comprehensive mechanical properties: hardness, bending strength and fracture toughness are 27.28 GPa, 405.11 MPa and 18.94 MPa·m1/2, respectively. The fracture mode of the B4C-TiB2 composite ceramics is a mixture of transgranular fracture and intergranular fracture. Two main two reasons for the ultra-high fracture toughness are the existence of lamellar graphite at the grain boundary, and the formation of a three-dimensional interpenetrating network covering the whole composite.

Annealed Treatment Effect on the Mechanical Properties of the Cf/SiC Composites Using Y2O3/ Al2O3 Additions

2014 ◽  
Vol 971-973 ◽  
pp. 7-10 ◽  
Author(s):  
Yun Long Zhang ◽  
Yu Min Zhang ◽  
Ming Hu ◽  
Jin Ping Li
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Rare Earth ◽  
Rare Earth Oxide ◽  
Crack Deflection ◽  
Sintering Additives ◽  
Improve Fracture Toughness ◽  
Sic Composites ◽  
Hot Pressing Sintering ◽  
Grain Bridging

In this investigation, the rare-earth oxide Y2O3combined with Al2O3served as sintering additives and commercial α-SiC powder were applied to fabricate Cf/SiC composites by hot-pressing sintering. The results proved that combination of Al2O3and Y2O3sintering additives was effective for densification of Cf/SiC composites. The influence of annealed temperature on the phase constitution, microstructure and mechanical properties of the Cf/SiC composites was detailed. The combination of grain bridging, crack deflection and fiber debonding can improve fracture toughness. Keywords: Pressing sintering, Mechanical Properties, Annealed Treatment

scholarly journals Effect of Additive Ti3SiC2 Content on the Mechanical Properties of B4C–TiB2 Composites Ceramics Sintered by Spark Plasma Sintering

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4616
Author(s):  
Xingheng Yan ◽  
Xingui Zhou ◽  
Honglei Wang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Spark Plasma Sintering ◽  
Bending Strength ◽  
High Fracture Toughness ◽  
Transgranular Fracture ◽  
Composite Ceramics ◽  
High Fracture ◽  
Plasma Sintering ◽  
Spark Plasma

B4C–TiB2 composite ceramics with ultra-high fracture toughness were successfully prepared via spark plasma sintering (SPS) at 1900 °C using B4C and Ti3SiC2 as raw materials. The results showed that compared with pure B4C ceramics sintered by SPS, the hardness of B4C–TiB2 composite ceramics was decreased, but the flexural strength and fracture toughness were significantly improved; the fracture toughness especially was greatly improved. When the content of Ti3SiC2 was 30 vol.%, the B4C–TiB2 composite ceramic had the best comprehensive mechanical properties: hardness, bending strength and fracture toughness were 27.28 GPa, 405.11 MPa and 18.94 MPa·m1/2, respectively. The fracture mode of the B4C–TiB2 composite ceramics was a mixture of transgranular fracture and intergranular fracture. Two main reasons for the ultra-high fracture toughness were the existence of lamellar graphite at the grain boundary, and the formation of a three-dimensional interpenetrating network covering the whole composite.

Effect of Sintering Pressure on Mechanical Properties of BN-Si3N4 Ceramic Composites Prepared by Spark Plasma Sintering

2016 ◽  
Vol 697 ◽  
pp. 188-192
Author(s):  
Jia Xin An ◽  
Wen Dong Xue ◽  
Feng Rui Zhai ◽  
Ruo Meng Xu ◽  
Jia Lin Sun
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Relative Density ◽  
Spark Plasma Sintering ◽  
Bending Strength ◽  
Raw Materials ◽  
Ceramic Composites ◽  
Composite Ceramics ◽  
Plasma Sintering ◽  
Spark Plasma

BN-Si3N4 composite ceramic wave-transparent materials with excellent mechanical properties were prepared by spark plasma sintering (SPS) using h-BN and α-Si3N4 powders as raw materials, Al2O3 and Y2O3 as sintering aids. The influence of sintering pressure on density and mechanical properties of BN-Si3N4 composite ceramics were studied. The phases were observed by X-ray diffraction (XRD), and the microstructures were identified by scanning electron microscopy (SEM). The results showed that with the sintering pressure increases, the relative density, bending strength and fracture toughness of the composite ceramics were significantly increased, and the porosity decreased rapidly. The effects of pressure on the properties of the composite ceramics was not significant at >40MPa, so 40MPa is optimal for the composite ceramics to gain good overall performance, i.e. the relative density was 89.1%, the porosity was 2.3%, the bending strength reached 215.4 MPa, and the fracture toughness was 3.1/MPa·m1/2.

scholarly journals Characterization of rare-earth doped Si3N4/SiC micro/nanocomposites

2010 ◽  
Vol 4 (1) ◽  
pp. 25-32 ◽  
Author(s):  
Peter Tatarko ◽  
Stefánia Lojanová ◽  
Ján Dusza ◽  
Pavol Sajgalík
Keyword(s):  
Fracture Toughness ◽  
Rare Earth ◽  
Silicon Nitride ◽  
Rare Earth Elements ◽  
Ionic Radius ◽  
Bending Strength ◽  
Rare Earth Oxide ◽  
Positive Influence ◽  
The Matrix

Influence of various rare-earth oxide additives (La2O3, Nd2O3, Sm2O3, Y2O3, Yb2O3 and Lu2O3) on the mechanical properties of hot-pressed silicon nitride and silicon nitride/silicon carbide micro/nano-composites has been investigated. The bimodal character of microstructures was observed in all studied materials where elongated ?-Si3N4 grains were embedded in the matrix of much finer Si3N4 grains. The fracture toughness values increased with decreasing ionic radius of rare-earth elements. The fracture toughness of composites was always lower than that of monoliths due to their finer Si3N4/SiC microstructures. Similarly, the hardness and bending strength values increased with decreasing ionic radius of rare-earth elements either in monoliths or composites. On the other hand, the positive influence of finer microstructure of the composites on strength was not observed due to the present defects in the form of SiC clusters and non-reacted carbon zones. Wear resistance at room temperature also increased with decreasing ionic radius of rare-earth element. Significantly improved creep resistance was observed in case either of composite materials or materials with smaller radius of RE3+. .

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.

Effects of Rare-Earth Oxides Doping on Microstructures and Properties of Al2O3/TiAl Composites

2011 ◽  
Vol 675-677 ◽  
pp. 143-146
Author(s):  
Fen Wang ◽  
Xiao Feng Wang ◽  
Jian Feng Zhu ◽  
Liu Yi Xiang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Rare Earth ◽  
Flexural Strength ◽  
Rare Earth Oxide ◽  
Rare Earth Oxides ◽  
Oxide Content ◽  
The Matrix ◽  
Al2o3 Particles ◽  
Positive Effect

Effects of rare-earth oxides addition (0.38~1.52 mol% of Sm2O3, Eu2O3 and Er2O3) on the property and microstructure of the hot-pressed (1300°C, 2h, 35 MPa) Al2O3 (12 wt %)/TiAl insitu composites have been investigated. The results show that the doping of rare-earth oxides has a positive effect on both mechanical properties and densities of Al2O3/TiAl composites. Densities enhanced with increasing of rare-earth oxides. The flexural strength and fracture toughness were higher than other samples when the rare-earth oxide content was 0.38 mol %. The matrix grains and Al2O3 particles were significantly refined, and Al2O3 particles evenly distributed in the matrix.

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.

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).

Sign in / Sign up

Export Citation Format

Share Document