Microstructure and toughening mechanism of the 3Y-TZP/Al2O3 composite reinforced by SiC whiskers

1996 ◽  
Vol 31 (24) ◽  
pp. 6637-6643 ◽  
Author(s):  
Fang-Fang Xu ◽  
Li-Tai Ma ◽  
Shu-Lin Wen
2012 ◽  
Vol 557-559 ◽  
pp. 772-775 ◽  
Author(s):  
Jin Ping Li ◽  
Song He Meng ◽  
Zhi Bo Wang ◽  
Qing Liu ◽  
Yu Min Zhang

The ZrC-20vol.%SiCw ultrahigh temperature ceramics with relative density of 99.2% can be prepared by hot pressing at 1900 oC and 30MPa for 60 min. The mechanical properties and microstructure of the composite were studied. The flexural strength and fracture toughness reaches up to 626.17MPa, 5.03 MPa•m1/2, respectively. SEM analysis shows the microstructure of the ZrC-20vol.%SiCw is homogeneous and SiC whiskers are uniformly distributed around the ZrC grains, which inhibit the ZrC grain growth during sintering. The fracture surface of ZrC-20vol.%SiCw reveals a mixture of intergranular and transgranular failure, and SiC whiskers play a remarkable role in improving the strength and toughness of ZrC matrix. The toughening mechanism of the composite is mainly fine-grain strengthening and whisker pull-out.


Author(s):  
Xue Zhang ◽  
Jin Du ◽  
Guosheng Su ◽  
Peirong Zhang ◽  
Yujing Sun ◽  
...  

Author(s):  
W. Braue ◽  
R.W. Carpenter ◽  
D.J. Smith

Whisker and fiber reinforcement has been established as an effective toughening concept for monolithic structural ceramics to overcome limited fracture toughness and brittleness. SiC whiskers in particular combine both high strength and elastic moduli with good thermal stability and are compatible with most oxide and nonoxide matrices. As the major toughening mechanisms - crack branching, deflection and bridging - in SiC whiskenreinforced Al2O3 and Si3N41 are critically dependent on interface properties, a detailed TEM investigation was conducted on whisker/matrix interfaces in these all-ceramic- composites.In this study we present HREM images obtained at 400 kV from β-SiC/α-Al2O3 and β-SiC/β-Si3N4 interfaces, as well as preliminary analytical data. The Al2O3- base composite was hotpressed at 1830 °C/60 MPa in vacuum and the Si3N4-base material at 1725 °C/30 MPa in argon atmosphere, respectively, adding a total of 6 vt.% (Y2O3 + Al2O3) to the latter to promote densification.


Author(s):  
J. Tong ◽  
L. Eyring

There is increasing interest in composites containing zirconia because of their high strength, fracture toughness, and its great influence on the chemical durability in glass. For the zirconia-silica system, monolithic glasses, fibers and coatings have been obtained. There is currently a great interest in designing zirconia-toughened alumina including exploration of the processing methods and the toughening mechanism.The possibility of forming nanocrystal composites by a phase separation method has been investigated in three systems: zirconia-alumina, zirconia-silica and zirconia-titania using HREM. The morphological observations initially suggest that the formation of nanocrystal composites by a phase separation method is possible in the zirconia-alumina and zirconia-silica systems, but impossible in the zirconia-titania system. The separation-produced grain size in silica-zirconia system is around 5 nm and is more uniform than that in the alumina-zirconia system in which the sizes of the small polyhedron grains are around 10 nm. In the titania-zirconia system, there is no obvious separation as was observed in die alumina-zirconia and silica-zirconia system.


2011 ◽  
Vol 49 (03) ◽  
pp. 231-236 ◽  
Author(s):  
Song-Lee Du ◽  
Sung-Hun Cho ◽  
In-Yong Ko ◽  
Jung-Mann Doh ◽  
Jin-Kook Yoon ◽  
...  

2021 ◽  
Author(s):  
Ruixue Zhang ◽  
Wanying Zhao ◽  
Zhenzhen Liu ◽  
Shanghai Wei ◽  
Yigang Yan ◽  
...  

In situ formed amorphous LiBH4·1/2NH3 on the surface of Al2O3 nanoparticles results in an enhanced ion conductivity of 1.1 × 10−3 S cm−1 at room temperature.


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