scholarly journals Study on high temperature sintering processes of selective laser sintered Al2O3/ZrO2/TiC ceramics

2009 ◽  
Vol 41 (1) ◽  
pp. 35-41 ◽  
Author(s):  
P. Bai ◽  
Y. Li
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
High Temperature ◽  
Mechanical Strength ◽  
Relative Density ◽  
Sintering Temperature ◽  
Sintering Time ◽  
Sintering Processes ◽  
Al2o3 Matrix

High temperature sintering processes of selective laser sintered Al2O3/ZrO2/TiC ceramics were studied. The effects of the sintering temperature and the sintering time on the relative density, strength and fracture toughness of Al2O3/ZrO2/TiC ceramics were investigated. The results showed that the sintering temperature and sintering time had a great effect on the relative density and the mechanical properties of Al2O3/ZrO2/TiC ceramics. The mechanical strength increased from 120MPa to 360MPa and KIC increased from 3.7 J/m2 to 6.9 J/m2 when the sintering temperature increased from 1400?C to 1600?C, however, the mechanical strength decreased rapidly from 370MPa to 330MPa and KIC decreased from 6.9 J/m2 to 6.1 J/m2 when the sintering time increased from 30min to 90min. Furthermore, the addition of TiC and ZrO2 in the Al2O3 matrix significantly improved mechanical strength and fracture toughness of the Al2O3 matrix ceramics.

Mechanical Properties and Microstructure of Al2O3/(W, Ti)C Nanocomposite

2008 ◽  
Vol 368-372 ◽  
pp. 717-720 ◽  
Author(s):  
Yong Hui Zhou ◽  
Xing Ai ◽  
Jun Zhao ◽  
Xun Liang Yuan ◽  
Qiang Xue
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Sintering Temperature ◽  
Crack Deflection ◽  
Nano Particles ◽  
Nano Scale ◽  
Sintering Time ◽  
Properties Of Materials ◽  
Al2o3 Matrix ◽  
Skeleton Structure

The Al2O3/(W, Ti)C nanocomposite was fabricated by hot pressing technique at 1650-1700°C under 30MPa for 10min. The fracture toughness remarkably increased by adding nano-scale Al2O3 (11vol %) particles into Al2O3 matrix. The flexural strength, fracture toughness and Vickers hardness are 840 MPa, 6.55 MPa•m1/ 2 and 20.1 GPa, respectively. The microstructure of the nanocomposite is homogenous skeleton structure. Nano particles could refine matrix grains and lead to the crack deflection as well as branching and bridging. The coexistence of nano-scale Al2O3, micro-scale Al2O3 and (W, Ti)C can reduce the sintering temperature and sintering time as well as the grain size, and improve the densification and mechanical properties of materials.

Effect of Sintering Temperature on Microstructure and Mechanical Properties of Al2O3-TiC-ZrO2 Ceramic Composites

2012 ◽  
Vol 476-478 ◽  
pp. 1031-1035
Author(s):  
Wei Min Liu ◽  
Xing Ai ◽  
Jun Zhao ◽  
Yong Hui Zhou
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Relative Density ◽  
Sintering Temperature ◽  
Ceramic Composites ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

Al2O3-TiC-ZrO2ceramic composites (ATZ) were fabricated by hot-pressed sintering. The phases and microstructure of the composites were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The relative density and mechanical properties (flexural strength, fracture toughness and Vicker’s hardness) of the composites were tested. The results show that the microstructure of the composites was the gray core-white rim. With the increase of sintering temperature, the relative density and mechanical properties of the composites increased first and then decreased. The composite sintered at 1705°C has the highest synthetical properties, and its relative density, flexural strength, fracture toughness and Vickers hardness are 98.3%,970MPa,6.0 MPa•m1/2and 20.5GPa, respectively.

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.

Effect of Iron Additive on the Sintering Behavior of Hot-Pressed ZrC-W Composites

2008 ◽  
Vol 368-372 ◽  
pp. 1764-1766 ◽  
Author(s):  
Yu Jin Wang ◽  
Lei Chen ◽  
Tai Quan Zhang ◽  
Yu Zhou
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Relative Density ◽  
Sintering Temperature ◽  
Sintering Behavior ◽  
Hot Press ◽  
Sintering Additive ◽  
Microstructure And Mechanical Properties ◽  
Hot Press Sintering

The ZrC-W composites with iron as sintering additive were fabricated by hot-press sintering. The densification, microstructure and mechanical properties of the composites were investigated. The incorporation of Fe beneficially promotes the densification of ZrC-W composites. The relative density of the composite sintered at 1900°C can attain 95.3%. W2C phase is also found in the ZrC-W composite sintered at 1700°C. The content of W2C decreases with the increase of sintering temperature. However, W2C phase is not identified in the composite sintered at 1900°C. The flexural strength and fracture toughness of the composites are strongly dependent on sintering temperature. The flexural strength and fracture toughness of ZrC-W composite sintered at optimized temperature of 1800°C are 438 MPa and 3.99 MPa·m1/2, respectively.

Mechanical Properties of La2O3-Al2O3 Ceramics Prepared by Microwave Sintering

2012 ◽  
Vol 519 ◽  
pp. 265-268 ◽  
Author(s):  
Yun Long Ai ◽  
Fei He ◽  
Bing Liang Liang ◽  
Wen He ◽  
Wei Hua Chen
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Draw Ratio ◽  
Sintering Temperature ◽  
Microwave Sintering ◽  
Microwave Energy ◽  
Pure Alumina ◽  
Sintering Time ◽  
Microstructure Evaluation ◽  
Columnar Grains

The influence of La2O3 on the phase and microstructure evaluation and mechanical properties of La2O3-Al2O3 ceramics sintered with 2.45 GHz microwave energy was investigated. The results showed that La2O3 could densify the pure alumina with a lower sintering temperature and a short sintering time. La2O3 reacted with Al2O3 to form LaAl11O18 completely and the amount of LaAl11O18 increased with the increasing content of La2O3, distributing at the Al2O3 grain boundaries. The specimen doped with 10 vol.% and 15 vol.% La2O3 sintered at 1500 °C exhibited plenty of columnar grains with draw ratio about 1:4. The existence of columnar grains enhanced the microhardness and fracture toughness of La2O3-Al2O3 ceramics.

Processing, mechanical properties and oxidation behavior of TaC and HfC composites containing 15 vol% TaSi2 or MoSi2

2009 ◽  
Vol 24 (6) ◽  
pp. 2056-2065 ◽  
Author(s):  
Diletta Sciti ◽  
Laura Silvestroni ◽  
Stefano Guicciardi ◽  
Daniele Dalle Fabbriche ◽  
Alida Bellosi
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
High Temperature ◽  
Mechanical Strength ◽  
Hot Pressing ◽  
Room Temperature ◽  
Oxidation Behavior ◽  
Temperature Stability ◽  
High Temperature Stability ◽  
Better Than

Fully dense HfC and TaC-based composites containing 15 vol% TaSi2 or MoSi2 were produced by hot pressing at 1750–1900 °C. TaSi2 enhanced the sinterability of the composites and nearly fully dense materials were obtained at lower temperatures than in the case of MoSi2-containing ones. The TaC-based composites performed better than HfC composites at room temperature, showing values of mechanical strength up to 900 MPa and a fracture toughness of 4.7 MPa·m1/2. However, preliminary oxidation tests carried out in air at 1600 °C revealed that HfC-based composites have a superior high temperature stability compared to TaC-based materials.

Microstructure and Mechanical Properties of ZrB2-Based UHTC via Reactive Hot Pressing

2008 ◽  
Vol 368-372 ◽  
pp. 1737-1739
Author(s):  
Qiang Qu ◽  
Wen Bo Han ◽  
Song He Meng ◽  
Xing Hong Zhang ◽  
Jie Cai Han
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Fracture Toughness ◽  
High Temperature ◽  
Hot Pressing ◽  
Sintering Temperature ◽  
Volume Ratio ◽  
Ultra High Temperature Ceramics ◽  
Reactive Hot Pressing

ZrB2-based ultra-high temperature ceramics (UHTCs) were prepared from a mixture powder of Zr/B4C/Si with different ratio via reactive hot pressing. The experimental results showed that the sintering temperature above 1800°C was necessary for enhancing the activity of the powders and thus improving the densification of the product. The sinterability and densification properties of ZrB2-based UHTCs meliorated with the amount of Si increasing. However, many large ZrB2 agglomerates formed when the amount of synthesized SiC in the product reached 25vol%, which led to decrease the mechanical property. The composite had highest mechanical properties when the volume ratio of ZrB2: SiC: ZrC was 73.86:20:6.14, and its flexual strength and the fracture toughness were 645.8MPa and 5.66MPa·m1/2 respectively. The microstructure investigation showed the in-situ formed SiC and ZrC were located in the triple point of ZrB2 grains with a size less than 3μm.

Influence of Hot Pressing Sintering Temperature and Time on Microstructure and Mechanical Properties of TiB2/Al2O3 Tool Materials

2012 ◽  
Vol 500 ◽  
pp. 629-633 ◽  
Author(s):  
Mei Lin Gu ◽  
Hong Jing Xu ◽  
Jian Hua Zhang ◽  
Zhi Wei
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Hot Pressing ◽  
Sintering Temperature ◽  
Three Point Bending ◽  
Sintering Time ◽  
Microstructure And Mechanical Properties ◽  
Hot Pressing Sintering ◽  
Increasing Temperature

In this paper, a TiB2/Al2O3composite was hot-pressed. The effect of hot pressing parameters on the TiB2/Al2O3composite microstructure and mechanical properties was investigated. The flexural strength and fracture toughness were measured by three point bending testing and direct indentation method, respectively. Experimental results show that the flexural strength decreases consistently with an increase in the sintering time, however, the fracture toughness increases consistently with an increase in the sintering time and sintering temperature. The maximum of the flexural strength is 1072 MPa at 1530 sintering temperature and 60 min sintering time. The microstructures were revealed by means of SEM. The results show that the TiB2grain size and density increases with the increasing temperature and time during hot pressing sintering, which benefits the fracture toughness and flexural strength.

Effect of B4C on the Mechanical Properties and Microstructure of ZrB2-SiC Based Ceramics

2010 ◽  
Vol 105-106 ◽  
pp. 218-221 ◽  
Author(s):  
Xuan Liu ◽  
Qiang Xu ◽  
Shi Zhen Zhu
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
High Temperature ◽  
Relative Density ◽  
Room Temperature ◽  
High Temperature Strength ◽  
Sintering Process ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Room Temperature Strength

ZrB2-SiC-B4C is sintered at 1700°C by spark plasma sintering process. The effect of B4C content on the mechanical properties and microstructure of ZrB2-SiC based ceramics is studied. The results show that, with the content of B4C increases, the relative density and room-temperature strength decrease in the ZrB2-SiC-B4C composite. The fracture toughness rises at first and then falls down. The high temperature strength increases.

Effect of Particle Size and Vacuum Sintering Temperature on Phase Composition and Mechanical Properties of WC-12 wt% Co Hardmetals

2012 ◽  
Vol 531-532 ◽  
pp. 3-7
Author(s):  
Shih Hsien Chang ◽  
Chung Wei Lee ◽  
Kuo Tsung Huang ◽  
Ming Wei Wu
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Particle Size ◽  
Relative Density ◽  
Sintering Temperature ◽  
Liquid Phase Sintering ◽  
Sintering Process ◽  
Vacuum Sintering ◽  
Brittle Phase ◽  
Effect Of Particle Size

The experimental results indicated that the WC-12wt% Co specimens showed excellent mechanical properties and microstructure by the optimal sintering process. The G5 specimen sintered at 1400°C/1 h achieved a relative density of 98% and a hardness of HRA 88.5. Meanwhile, the TRS increased to 2400 MPa. F12 specimens that sintered at 1350°C/1 h achieved a relative density of 99% and a hardness of HRA 92.5. The TRS was also enhanced to 2170 MPa. In this study, the η phase (Co3W3C) precipitated at a high sintering temperature. The precipitations generated by liquid phase sintering gathered in some specific regions of the specimens and reacted with the WC particles. In addition, Co3W3C was a hard and brittle phase that resulted in a low TRS for the specimens; and a large amount of η phases were detrimental to the fracture toughness of the specimens.

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