Combining 2D and 3D characterization techniques for determining effects of HIP-rejuvenation after fatigue testing of SX microstructures

A hot isostatic pressing rejuvenation heat treatment is applied to a CMSX-4 type SX superalloy after it has been subjected to a low cycle fatigue test to rupture. The evolution of microstructural defects, such as pores and cracks which are present after fatigue, has been tracked in 3D by X-ray tomography before and after rejuvenation. From the rejuvenated specimen series of metallographic cross sections were prepared and investigated by scanning electron microscopy for getting complementary 2D information at high resolution. The micrographs were stitched to a panorama which was then matched into the 3D representation of the specimen volume. By combining 3D and 2D data, statistical volume related quantities were achieved while detailed characteristics have been assigned to individual defects present in the 2D panorama micrograph. This technique is in general appropriate for length-scale bridging microstructural investigations. Results of the performed investigations concerning the rejuvenation effect on the microstructure are presented and discussed

Организационная культура в контексте социолого-управленческого подхода: новые аспекты феномена

Рассматриваются особенности нового социолого-управленческого подхода, обосновывается, что он является комплексным, сочетающим системный, деятельностный и феноменологический подходы. Возможность сочетания в одном подходе трех других базируется на полипарадигмальности социологии. Методы. Основу исследования составляют фундаментальные идеи социологии, сравнительный анализ, междисциплинарный подход. Результаты. Организационная культура анализируется с позиции социолого-управленческого подхода. Он позволяет рассматривать организационную культуру как объективно-субъективное образование в единстве трех составляющих. На основе первой составляющей, базирующейся на системном подходе, культура организации рассматривается как сложная система. На основании второй составляющей, базирующейся на деятельностления», как способ деятельности организации. Третья составляющая, базирующаяся на феноменологическом подходе, позволяет говорить о культуре организации как о культурном поле конструирования социальной реальности. Будучи системной, культура организации имеет ряд особенных свойств. Подход к организационной культуре как «субъекту управления» позволяет выявить такие ее особенности, как способность регулировать действия индивидов, упорядочивание организационных социальных процессов, придание смысла существования, объединение индивидов в общие социокультурные пространства, участие в преобразованиях и вещей, и человека. В пределах культуры организации осуществляется постоянное конструирование социальной реальности. В результате организации предстают как системы, в которых коллективные действия сознательно координируются. Социолого-управленческий подход получил эмпирическую проверку в процессе исследования организационной культуры организаций малого бизнеса.The author considers the features of the new sociologic-management approach and justifies that it is integrated, combining system, activity and phenomenological approaches. The possibility of combining three other approaches in one is based on polyparadigmality of sociology. Methods. Fundamental sociological ideas, comparative analysis, interdisciplinary approach are foundation of the research. The results. The sociological and managerial approach is applied to such a phenomenon of social reality as an organizational culture. The sociological and managerial approach focuses on the fact that organizational culture as an objectively-subjective entity is a complex system (a systematic approach), first of all, included in higher-level systems. It has a complex system structure. Secondly, it is a «subject of management» and it characterizes the way the organization works (activity approach). Thirdly, it is a cultural area for construction of social reality (a phenomenological approach). As a complex system, the organization culture has a complex internal structure and is characterized by a number of essential properties. Organizational culture as a «subject of management » regulates the actions of people, social processes in the organization, gives meaning orientation through ensuring the continuity of social experience, socialization, integration of people into unified sociocultural continuums, the common cultural area, participates in the transformation of human beings. As a result, organizations appear as systems in which collective actions are consciously coordinated. The sociological and managerial approach has been empirically tested in investigation of the organizational culture of small business organizations

Manufacturing of W/steel composites using electro-discharge sintering process

Tungsten-steel metal matrix composites are consolidated using electro-discharge sintering. At first steel and tungsten powders are sintered separately and then 25 vol% W, 50 vol% W and 75 vol% W mixed powders are sintered. A thorough process parametric study is carried out involving analysis of the influence of particle size distribution, sintering pressure, and discharge energy on the maximum discharge current and obtained residual porosity. Thermal expansion coefficient and the specific heat capacity of the optimized sintered composites are almost same as their theoretical values, however the thermal conductivities and the mechanical properties are lower than the expected values

Micro-magnetic and microstructural characterization of wear progress on case-hardened 16MnCr5 gear wheels

The evaluation of wear progress of gear tooth flanks made of 16MnCr5 was performed using non-destructive micro-magnetic testing, specifically Barkhausen noise (BN) and incremental permeability (IP). Based on the physical interaction of the microstructure with the magnetic field, the micro-magnetic characterization allowed the analysis of changes of microstructure caused by wear, including phase transformation and development of residual stresses. Due to wide parameter variation and application of bandpass filter frequencies of micro-magnetic signals, it was possible to indicate and separate the main damage mechanisms considering the wear development. It could be shown that the maximum amplitude of BN correlates directly with the profile form deviation and increases with the progress of wear. Surface investigations via optical and scanning electron microscopy indicated strong surface fatigue wear with micro-pitting and micro-cracks, evident in cross-section after 3 × 105 cycles. The result of fatigue on the surface layer was the decrease of residual compression stresses, which was indicated by means of coercivity by BN-analysis. The different topographies of the surfaces, characterized via confocal white light microscopy, were also reflected in maximum BN-amplitude. Using complementary microscopic characterization in the cross-section, a strong correlation between micro-magnetic parameters and microstructure was confirmed and wear progress was characterized in dependence of depth under the wear surface. The phase transformation of retained austenite into martensite according to wear development, measured by means of X-ray diffraction (XRD) and electron backscatter diffraction (EBSD) was also detected by micro-magnetic testing by IP-analysis

Densification of NdFeB magnets by electro-discharge sintering - Microstructure, mechanical and magnetic properties

In this work, the densification process of nanocrystalline NdFeB powder by electro-discharge sintering (EDS) was investigated. The EDS technique is used as a fast and energy-saving compaction process for metal powders. In contrast to the spark plasma sintering (SPS) process, EDS has not received much attention during recent years. SPS is a low voltage, direct current, pulsed current-activated, and pressure-assisted sintering process. Whereas EDS is also pressure-assisted, but uses electrical energy discharged from capacitors to densify conductive powders. During EDS a large current is discharged within 5 ms from capacitors into a pre-compacted loose powder, thus resulting in complete compaction. Please click Additional Files below to see the full abstract