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Experimental study of Ni-based single-crystal superalloy: Microstructure evolution and work hardening of ground subsurface

Xu Yunchao, Gong Yadong, Wang Zhongxu, Wen Xuelong, Yin Guoqiang, Zhang Huan, Qi Yang

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 2

74--84

EN

In the present study, the grinding experiment of second-generation nickel-based single-crystal superalloy DD5 was carried out under different grinding parameters. The grinding force was recorded during the grinding process, and it was found that it decreased with increasing grinding speed and increased with feed speed. The microstructure evolution of ground subsurface was obtained by optical microscope (OM) and scanning electron microscope (SEM), and the elemental distribution of γ/γ' phases was investigated by energy dispersion spectrum (EDS). The results show that there are two layers different from the bulk material beneath the ground surface: (i) a white layer (WL) with no obvious structural features under limited observation scale and (ii) a severe deformed layer (SDL) with the elongated and rotated γ' phase and the narrowed γ channel. Elements segregation behavior exists in both the white layer and severe deformed layer. The grinding parameters have a great influence on the thickness of the white layer, which is due to the elemental diffusion behavior caused by intensive thermo-mechanical load. There is work hardening in the white layer, and the hardening degree aggravates with the increase in cutting speed and feed speed.

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Comparison of solutions for microseismic focal mechanism estimation

Wandycz P., Święch E., Pasternacki A.

Geology, Geophysics and Environment

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2016

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Vol. 42, no. 1

137--138

EN

One of the major advantages of microseismic data, recorded during hydraulic fracturing of prospective shale intervals is ability to use both P and S wave in the analysis, not only to determine epicentral locations of events but also to describe source itself. The information about the mechanisms of located microseismic events allows better understanding of in situ stress and strain conditions and the local subsurface geomechanical properties and forces (Kamei et al. 2015). As Duncan stated in his work, a proper characterization of the observed events mechanisms is the key to understand radiation pattern of the signals in the investigated area (Duncan & Eisner 2010). Moreover, an understanding of the nature of the rock failure supports reservoir simulation models and stimulated reservoir volume estimates (Kratz & Thorton 2016). Proper assessment of event strike, dip and rake provides the geometry of the fracture plane assuming double couple focal mechanism, while full moment tensor inversion provides information about shear and tensile nature of the calculated mechanisms. The common method to obtain reliable focal mechanisms of observed microseismic events is decomposing of the full moment tensor. Seismic moment tensor is powerful tool which provides a general mathematical solution of sources that can be used to distinguish between various types of microseismic events. The method comes to reliably estimation of the six independent components of a full moment tensor by lestsquares inversion (Eaton & Forouhideh 2010). The motivation for this analysis was to determine microseismic focal mechanisms based on P – wave peak amplitude, P and S – waves peak amplitudes and S – wave peak amplitude only to estimate the differences and uncertainties between these three different solutions. Furthermore authors decided to check how the mechanisms changes with different geometries of downhole monitoring array. In this study only synthetic data computed in MiVu GeoTomo software using raytracing method and simple layered velocity model were used. The mentioned velocity model was constructed based on well logs data delivered by PGNiG from measurements done in Northern Poland where active exploration of shale gas takes place. In this analysis authors focused only on double couple (DC) and compensated linear vector dipole (CLVD) mechanisms which are two most common types of microseismic focal mechanisms occur during hydraulic fracturing of shale deposits. Performed analysis proved that the best and most consistent results with the lowest uncertainties reflected in the condition number parameter can be obtained by using both P and S peak amplitudes.

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Wpływ wykrojów kształtowych na zamykanie się wad podpowierzchniowych w procesie walcowania

Sobczak K., Dyja H., Kawałek A.

Hutnik, Wiadomości Hutnicze

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2014

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Vol. 81, nr 8

590--594

PL

W artykule omówiono wpływ nowej metody walcowania w wykrojach kształtowych na zamykanie się wad podpowierzchniowych we wlewkach ciągłych. Do badań zastosowano stal konstrukcyjną S355J2G3, oraz ołów. Przeprowadzono modelowanie numeryczne przy użyciu programu komputerowego Forge 2008®. Badania doświadczalne przeprowadzono przy użyciu walcarki laboratoryjnej D150. Badano pola powierzchni wad po walcowaniu. W badaniach numerycznych, jak i eksperymentalnych, w próbkach stalowych i ołowianych nieciągłości po walcowaniu w trzecim przepuście zamykały się średnio w 99%. Stwierdzono, że kształt wykrojów wpływa na efektywniejsze zamykanie się wad podpowierzchniowych.

EN

The article discusses problems related to the influence of rolling processes on the process of closing of subsurface discontinuities in continuous castings during rolling in slitting − bending grooves. The numerical simulations were carried out using the Forge 2008® software programme. In the research, the S355J2G3 structural steel and lead were used. The experimental studies were conducted in a D150 laboratory rolling mill. Their surface areas of defects after rolling were examined. In numerical and experimental studies, in steel samples after rolling in the third rolling stand, the defects were closing in 99% on average. It was stated that the effectiveness of closing of subsurface material discontinuities in feedstock is strongly influenced by the shape of the rolling groove.

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Wpływ metodologii przetwarzania na wyniki statycznego modelowania 3D

Papiernik B.

Prace Naukowe Instytutu Nafty i Gazu

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2010

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nr 170 wyd. konferencyjne

213--217

PL

Przestrzenne modelowanie geologiczne, tzw. modelowanie statyczne jest podstawowym narzędziem ilościowej analizy budowy struktur wgłębnych. Uzyskiwane wyniki modelowania zależą w dużym stopniu od zastosowanej procedury przetwarzania. W artykule zilustrowano tą tezę na dwóch przykładach. Pokazano wpływ zmian parametrów krigingu na 2D model prędkości opracowany na podstawie danych z niecki miechowskiej. Porównano również wyniki modelowania algorytmami deterministycznym (kriging) i stochastycznymi (algorytmy sekwencyjne Petrela) w rejonie antykliny Zaosia.

EN

Spatial (3D) geomodeling, so called structural-parametric modeling, belongs to basic tools of the quantitative subsurface analysis. Modeling results are strongly dependent on numerical routines applied. That thesis was illustrated in the paper with two case studies. The influence of kriging settings on the 2D velocity model was demonstrated using data from the Miechow Though. The author also compared results of the 3D lithologic and parametrical modeling with the use of the deterministic algorithm (kriging) and the stochastic simulation techniques (Petrel sequential algorithms) in the Zaosie Anticline area.