High-Speed End Electric Discharge Milling of Silicon Carbide Ceramics

2011 ◽  
Vol 26 (8) ◽  
pp. 1050-1058 ◽  
Author(s):  
Renjie Ji ◽  
Yonghong Liu ◽  
Yanzhen Zhang ◽  
Baoping Cai ◽  
Xiaopeng Li
Author(s):  
Pascal Forquin ◽  
Edward Ando

Silicon carbide ceramics are widely used in personal body armour and protective solutions. However, during impact, an intense fragmentation develops in the ceramic tile due to high-strain-rate tensile loadings. In this work, microtomography equipment was used to analyse the fragmentation patterns of two silicon carbide grades subjected to edge-on impact (EOI) tests. The EOI experiments were conducted in two configurations. The so-called open configuration relies on the use of an ultra-high-speed camera to visualize the fragmentation process with an interframe time set to 1 µs. The so-called sarcophagus configuration consists in confining the target in a metallic casing to avoid any dispersion of fragments. The target is infiltrated after impact so the final damage pattern is entirely scanned using X-ray tomography and a microfocus source. Thereafter, a three-dimensional (3D) segmentation algorithm was tested and applied in order to separate fragments in 3D allowing a particle size distribution to be obtained. Significant differences between the two specimens of different SiC grades were noted. To explain such experimental results, numerical simulations were conducted considering the Denoual–Forquin–Hild anisotropic damage model. According to the calculations, the difference of crack pattern in EOI tests is related to the population of defects within the two ceramics. This article is part of the themed issue ‘Experimental testing and modelling of brittle materials at high strain rates’.


2012 ◽  
Vol 57 (4) ◽  
pp. 421-434 ◽  
Author(s):  
RenJie Ji ◽  
YongHong Liu ◽  
YanZhen Zhang ◽  
Fei Wang ◽  
BaoPing Cai ◽  
...  

2012 ◽  
Vol 27 (9) ◽  
pp. 965-969
Author(s):  
Xiao YANG ◽  
Xue-Jian LIU ◽  
Zheng-Ren HUANG ◽  
Gui-Ling LIU ◽  
Xiu-Min YAO

2013 ◽  
Vol 39 (1) ◽  
pp. 841-845 ◽  
Author(s):  
Xiao Yang ◽  
Xuejian Liu ◽  
Zhengren Huang ◽  
Xiuming Yao ◽  
Guiling Liu

1989 ◽  
Vol 97 (1131) ◽  
pp. 1348-1353
Author(s):  
Tadahisa ARAHORI ◽  
Nobuya IWAMOTO

1995 ◽  
Vol 10 (12) ◽  
pp. 3232-3240 ◽  
Author(s):  
Linus U.J.T. Ogbuji ◽  
M. Singh

The oxidation behavior of reaction-formed silicon carbide (RFSC) ceramics was investigated in the temperature range of 1100 to 1400 °C. The oxidation weight change was recorded by TGA; the oxidized materials were examined by light and electron microscopy, and the oxidation product by x-ray diffraction analysis (XRD). The materials exhibited initial weight loss, followed by passive weight gain (with enhanced parabolic rates, kp), and ending with a negative (logarithmic) deviation from the parabolic law. The weight loss arose from the oxidation of residual carbon, and the enhanced kp values from internal oxidation and the oxidation of residual silicon, while the logarithmic kinetics is thought to have resulted from crystallization of the oxide. The presence of a small amount of MoSi2 in the RFSC material caused a further increase in the oxidation rate. The only solid oxidation product for all temperatures studied was silica.


Author(s):  
E. G. Pashuk ◽  
G. D Kardashova ◽  
Sh. A. Khalilov

The paper discusses the possibility of using resonant ultrasonic spectroscopy (RUS) as a source of information for the physics and technology of obtaining silicon carbide ceramics by the example of samples of the composition SiC ‒ 25 % AlN, obtained by the method of spark plasma sintering. The possibility of obtaining a complete set of elastic moduli (EM) of samples with an error of less than 1 % is shown. At the same time, the requirements for surface quality are significantly reduced. The revealed functional relationship between EM and porosity makes it possible to create a non-destructive method of porosity control and calculate the elastic moduli at zero porosity (i. e., the elastic modulus of the ceramic matrix EM0). Comparison of EM0 samples obtained at different parameters of the technological process allows determining their optima values..


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