Strength of Crack Healed-Specimen and Elastic Wave Characteristics of Al2O3/SiC Composite Ceramics

2007 ◽  
Vol 31 (4) ◽  
pp. 425-431 ◽  
Author(s):  
Hae-Suk Kim ◽  
Mi-Gyeong Kim ◽  
Jin-Uk Kim ◽  
Seok-Hwan An ◽  
Gi-U Nam
2007 ◽  
Vol 353-358 ◽  
pp. 345-348
Author(s):  
Ki Woo Nam ◽  
B.G. Ahn ◽  
M.K. Kim ◽  
C.S. Son ◽  
Jin Wook Kim ◽  
...  

The optimized conditions of pressureless sintering were investigated in order to obtain the bending strength and the elastic wave signal of Al2O3 composite ceramics for textiles machinery. As sintering conditions, a temperature range from 1400°C to 1700°C and time from 30 minutes to 150 minutes were applied. Three-point bending tests were conducted on the sintered materials to obtain the strength property. From the test results, the optimum sintering condition was 1600°C, 100 minutes. Al2O3 composite ceramics showed that the elastic wave signal characteristics had a regular correlativity between the optimum sintering temperature and time as well as the maximum bending strength.


Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2194 ◽  
Author(s):  
Pouyan Talebizadehsardari ◽  
Arameh Eyvazian ◽  
Farayi Musharavati ◽  
Roohollah Babaei Mahani ◽  
Tamer A. Sebaey

This work aims at analyzing elastic wave characteristics in a polymeric nanocomposite curved beam reinforced by graphene nanoplatelets (GNPs). GNPs are adopted as a nanofiller inside the matrix to enhance the effective properties, which are approximated through Halpin-Tasi model and a modified rule of mixture. A higher-order shear deformation theory accounting for thickness stretching and the general strain gradient model to have both nonlocality and strain gradient size-dependency phenomena are adopted to model the nanobeam. A virtual work of Hamilton statement is utilized to get the governing motion equations and is solved in conjunction with the harmonic solution procedure. A comparative study shows the effects of small-scale coefficients, opening angle, weight fraction, the total number of layers in GNPs, and wave numbers on the propagation of waves in reinforced nanocomposite curved beams. This work is also developed for two different distribution of GNPs in a polymeric matrix, namely uniformly distribution and functionally graded one.


2006 ◽  
Vol 20 (25n27) ◽  
pp. 4279-4284 ◽  
Author(s):  
KI WOO NAM ◽  
MI KYUNG KIM ◽  
HAE SOOK KIM ◽  
JIN WOOK KIM ◽  
SEOK HWAN AHN

This paper describes the investigation of bending strength and elastic wave signal characteristics of Si 3 N 4 monolithic and Si 3 N 4/ SiC composite ceramics with crack healing ability. The elastic wave signals, generated during the compression load by a Vickers indenter on the brittle materials, were recorded in real time, and the AE signals were analyzed by the time-frequency analysis method. The three-point bending test was performed on the Si 3 N 4 monolithic and Si 3 N 4/ SiC composite ceramic specimens with/without crack-healed. Consequently the bending strength of the crack-healed specimens at 1300°C was completely recovered up to that of the smooth specimens. And the frequency properties of crack-healed specimens tended to be similar to the distribution of the dominant smooth specimens frequency. This study suggests that the results of the signal information for the anisotropic ceramics show a feasible technique to guarantee structural integrity of a ceramic component.


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