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Characterizing the Effects of Hot Isostatic Pressing on IN713C Superalloy Blade Microstructure by Electron Backscatter Diffraction

100%

Chmiela B., Kościelniak B., Roskosz S.

Acta Physica Polonica A

2016

vol. 130

issue 4

1097-1099

The integrity of turbine blades is essential for the safe operation of jet engines. Thus, the mechanical properties, especially creep resistance and fatigue strength at high temperatures, must be thoroughly optimized. In particular, it has previously been observed that the mechanical properties of blades depend on the microstructure and porosity resulting from the casting process. To decrease the internal porosity generated by investment casting, hot isostatic pressing can be applied. This paper aims to evaluate the effects of hot isostatic pressing on the microstructure of IN713C alloy blades. Two variants of hot isostatic pressing treatment, differing in pressure, were carried out, and each resulted in lowered porosity. Microstructural investigations, performed using scanning electron microscopy and electron backscatter diffraction revealed significant changes of γ' particles and high strain intensity in the surface layer of the blades after hot isostatic pressing treatment.

Modeling the Nonlinear Dynamics of Nanotube Cores Driven by Interlayer Dispersion Force Modulation: New Developments and Future Applications

88%

Pinto F.

Acta Physica Polonica A

2016

vol. 129

issue 4

819-825

Despite several past proposals to employ the inner cores of multiwalled nanotubes as, among others, ultra-high-frequency oscillators, memory devices, and nano-scale sensors, driving into motion a mass initially at rest within the nanotube outer walls has remained a crippling practical obstacle. In addition to the challenge of applying an external driving force upon the entirely embedded shuttle, it has been reported that the dynamics of such motion is "truly nonlinear", that is, it cannot be reduced to that of harmonic or nearly-harmonic oscillators even in the case of vanishing amplitudes. The author has shown that, since friction is nearly negligible, the inner core can be set into motion by breaking the high axial symmetry of the interlayer dispersion forces exerted on it by the outer walls. For instance, by fabricating nanotubes with even just two segments having slightly different dielectric properties, it was concluded that the motion of a partially extruded core under the action of an external electric field could be remarkably stabilized and electrical energy could be both stored into and released from the van der Waals field. Further significant progress was made by identifying a possible mechanism for the time-modulation of the spectral properties of double-walled nanotubes by acting on the free-carrier exciton screening in semiconducting nanotubes. In this paper, new developments are presented in the accurate mathematical modeling of these complex driven systems and additional future applications of telescoping nanotubes as actuators, non-electrochemical energy nanostorage systems, and neutral particle accelerators are illustrated.

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2 Acta Physica Polonica A

2 2016

1 Chmiela B.

1 Kościelniak B.

1 Pinto F.

1 Roskosz S.

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Characterizing the Effects of Hot Isostatic Pressing on IN713C Superalloy Blade Microstructure by Electron Backscatter Diffraction

Modeling the Nonlinear Dynamics of Nanotube Cores Driven by Interlayer Dispersion Force Modulation: New Developments and Future Applications