Characterization of the elastic modulus of ceramic–metal composites with physical and mechanical properties by ultrasonic technique

Abstract

The scope of this study, that is, the effect of the elastic modulus obtained by ultrasonic method on the physical and mechanical properties of tungsten carbide (WC)-based ceramic–metal composites, which have Ni and Co metallic binder composition produced by powder metallurgy and represented by high strength and hardness criteria, was investigated. In order to obtain composite samples in the study, it was sintered in a microwave furnace at different temperatures to combine the powder particles prepared at the rate of 60% Ni, 20% Co, and 20% WC by weight. Then, the velocities and longitudinal attenuation values of longitudinal and shear ultrasonic waves along the composite sample were measured using the ultrasonic pulse-echo method. The elastic modulus of the composites was determined using ultrasonic velocities and sample density. Hardness testing, scanning electron microscopy (SEM), and X-ray diffraction (XRD) analyses were also performed. The results show that the elastic modulus increases with the increase in sintering temperature and ultrasonic wave speeds, but decreases with the longitudinal attenuation value, considering the SEM images and XRD analysis. There is also a linear relationship between elastic modulus and stiffness.

Making the Case for Scaling Up Microwave Sintering of Ceramics

“…Various mechanical and metallurgical techniques like X-ray diffraction, scanning electron microscopy, energy-dispersive spectroscopy, [61,62] Vicker's microhardness, porosity measurement, Archimedes density measurement, and flexural study are utilized in order to characterize the sintered ceramic samples. [63] However, these techniques analyze the samples after they have been sintered. In order to perform in situ characterizations, techniques like X-ray diffraction, micro-CT, and pair distribution function analysis have been utilized to collect data while the sample is being sintered (Figure 4B).…”

Porosity dependence of sound velocities in partially sintered alumina, zirconia, ATZ, and mullite ceramics

“…A direct knowledge of the sound wave velocity is indispensable in many applications, for example, in seismology they provide information about the Earth's interior, 1,2 in many fields of engineering they are required for thickness measurements and defectoscopy 3–5 . Ultrasonic testing has also become an important tool to determine the elastic properties of materials 4,6–10 . Other contexts in which the sound velocity plays a role are ceramics processing, where sound velocity measurements enable direct monitoring of manufacturing stages, 11 assessment of the ballistic efficiency of ceramics, 12,13 determination of the acoustical performance of wall and floor tiles 14 or evaluation of the resistance of structural ceramics against shock loads.…”

“…[3][4][5] Ultrasonic testing has also become an important tool to determine the elastic properties of materials. 4,[6][7][8][9][10] Other contexts in which the sound velocity plays a role are ceramics processing, where sound velocity measurements enable direct monitoring of manufacturing stages ,11 assessment of the ballistic efficiency of ceramics, 12,13 determination of the acoustical performance of wall and floor tiles 14 or evaluation of the resistance of structural ceramics against shock loads .15 Despite the importance of sound velocities in many contexts and its obvious porosity dependence, the literature in this field is full of misconceptions concerning the character of this porosity dependence. Even in works specifically dedicated to the seismic velocities, 16 it is assumed that the sound velocities should follow a simple (Spriggs-type) exponential relation, 17,18 which is not possible (i.e., not admissible on physical grounds) unless fundamental laws of physics, namely, the upper Hashin-Shtrikman bounds 19 are to be violated.…”