Incorporation of Y2O3 Particles into 410L Stainless Steel by a Powder Metallurgy Route

Addition of yttria to steels has been proposed for the fabrication of oxide-dispersion-strengthened materials for nuclear power applications. We have investigated materials prepared from 12 Cr martensitic stainless steel, AISI 410L, produced by powder metallurgy. Materials were produced with and without yttria addition, and two different sizes of yttria were used, 0.9 µm and 50 nm. Tensile and mini-creep tests were performed to determine mechanical properties. Optical microscopy, SEM, TEM, and EDX analysis were used to investigate the microstructures and deformation mechanisms and to obtain information about non-metallic inclusion particles. SiO2, MnS, and Y2Si2O7 inclusion particles were observed. An SiO2 and Y2O3 interaction was seen to have occurred during the ball milling, which impaired the final mechanical properties. Small-angle neutron scattering experiments showed that the matrix chemistry prevented effective dissolution of the yttria. © The Author(s) 201

Consumer Understanding and Use of the New Nutritional Label: A Pilot Study

This paper will explore both the ways in which the practices of self-care, specifically related to mental health, have emerged as responses to the increasingly precarious status of life after the economic shocks of the Global Financial Crisis (GFC), whilst also looking to the work of Silvia Federici and Kathi Weeks to propose models for immanent critique of these practices. Although it cannot be taken as a pure origin, post-GFC mental health discourse has increasingly seen mental health discussed as a form of resilience to precarity. Furthermore, practices of self-care, and psychological forms of treatment such as cognitive behavioural therapy (CBT) have become vehicles for the intensification of personal resilience in the face of systemic crisis. If self-care involves an inward looking and depoliticised subject, surely political emancipation lies elsewhere. The possibility of some alternative to our present state of affairs, where self-care increasingly appears as a form of ‘voluntary servitude,’ that is to say, a form of self-subjugation with serious political risks, must surely be taken as a continual project for those engaged in critical inquiry. Then again, to suggest that those engaging in self-care are simply reproducing neoliberal subjectivity would surely miss the ways in which such forms of self-preservation might appear as unavoidable for the individuals in question. Through an engagement with their work—and one that draws parallels between their strategic critiques of reproductive labour broadly speaking, and the more specific area of mental illness and neoliberal governmentality—the question of the “necessity” of self-care will be brought into alignment with the possibilities of its practicality

Microstructural stability of ODS steels in cyclic loading

The remarkable microstructural stability of high chromium steels prepared by powder metallurgy and strengthened by dispersion of nanometric yttrium oxides in cyclic loading at high temperatures is reported. Contrary to the continuous cyclic softening and profound changes in the microstructure during fatigue of common high chromium steels, the addition of 0.3wt% Y2O3 stabilizes the microstructure and significantly reduces cyclic softening of investigated steels. The evolution of microstructure as a result of fatigue loading at room temperature, 650 and 750 degrees C, was examined by means of transmission electron microscopy. Only minor changes in the microstructure were detected. The stability of oxide particles after high-temperature exposure was confirmed by energy dispersion spectroscopy chemical analysis. The microstructural features are discussed in relation to the cyclic behaviour of the oxide dispersion strengthened steels. The analysis of the hysteresis loop indicates that oxide nanoclusters are intersected and dissolved in slip bands of ODS Eurofer steel. This process contributes to cyclic softening

Imaging of Magnetic Domain Structure in FeSi/Mn0.8Zn0.2Fe2O4FeSi/Mn_{0.8}Zn_{0.2}Fe_2O_4 Composite using Magnetic Force Microscopy

Soft magnetic composite was prepared by coating the commercial FeSi powder by $Mn_{0.8}Zn_{0.2}Fe_2O_4$ (MnZn) ferrite, which serves as a potential dielectric phase. MnZn ferrite was prepared by the sol-gel method followed by the auto-self combustion process. The spinel structure of MnZn ferrite was analyzed by X-ray diffraction technique. The composite material was prepared by uniaxial compaction technique and sintered either by conventional or unconventional microwave method. The microwave sintering was applied in order to reduce a grain growth and decrease the overall sintering time. The microstructure of FeSi powder is formed by grains of different diameter. Magnetic force microscopy and scanning electron microscopy were used for an investigation of the correlation between the grain size, grain boundaries and magnetic domains. Magnetic force microscopy visualization of magnetic domains in the prepared soft magnetic composite brings insight into how the magnetically active coating (MnZn ferrite) influences the soft magnetic (FeSi) powder under the influence of the external magnetic field

In situ characterization of a high work hardening Ti-6Al-4V prepared by electron beam melting

A multi-phase Ti-6Al-4V prepared by electron beam melting and thermal post treatments has been shown to exhibit increased strength and ductility over standard wrought or hot isostatic pressed Ti-6-Al-4V. The mechanical improvements are due to a prolonged, continuous work hardening effect not commonly observed in Ti alloys. In situ x-ray diffraction and high resolution digital image correlation are used to examine the strain partitioning between the phases during tensile loading with post-mortem electron microscopy to characterize the deformation behavior in each phase. Specimens heat treated between 850 and 980 degrees C were tested and the effect of annealing temperature on the micromechanical response is discussed. It is shown that the work hardening is the result of composite load-sharing behavior between three mechanically distinct microstructures: large a lamellae and a martensitic region of fine acicular alpha' and a third phase not previously reported in this alloy. (C) 2019 Acta Materialia Inc. Published by Elsevier Ltd