66 research outputs found

    The Pleasure of Punishment

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    Based on a reading of contemporary philosophical arguments, this book accounts for how punishment has provided audiences with pleasure in different historical contexts. Watching tragedies, contemplating hell, attending executions, or imagining prisons have generated pleasure, according to contemporary observers, in ancient Greece, in medieval Catholic Europe, in the early-modern absolutist states, and in the post-1968 Western world. The pleasure was often judged morally problematic, and raised questions about which desires were satisfied, and what the enjoyment was like. This book offers a research synthesis that ties together existing work on the pleasure of punishment. It considers how the shared joys of punishment gradually disappeared from the public view at a precise historic conjuncture, and explores whether arguments about the carnivalesque character of cruelty can provide support for the continued existence of penal pleasure. Towards the end of this book, the reader will discover, if willing to go along and follow desire to places which are full of pain and suffering, that deeply entwined with the desire for punishment, there is also the desire for social justice. An accessible and compelling read, this book will appeal to students and scholars of criminology, sociology, philosophy and all those interested in the pleasures of punishment

    Influence of heat treatment on the microstructure and tensile properties of Ni-base superalloy Haynes 282

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    The effect of heat treatment on the microstructure and mechanical properties of Ni-base superalloy Haynes 282 was investigated. Applying a standard two-step ageing (1010 °C/2 h +788 °C/8 h) to the as-received, mill annealed, material resulted in a the presence of discrete grain boundary carbides and finely dispersed intragranular γ′, with an average size of 43 nm. This condition showed excellent room temperature strength and ductility. The introduction of an additional solution treatment at 1120 °C resulted in grain growth, interconnected grain boundary carbides and coarse (100 nm) intragranular γ′. The coarser γ′ led to a significant reduction in the strength level, and the interconnected carbides resulted in quasi-brittle fracture with a 50% reduction in ductility. Reducing the temperature of the stabilization step to 996 °C during ageing of the mill annealed material produced a bi-modal γ′ distribution, and grain boundaries decorated by discrete carbides accompanied by γ′. This condition showed very similar strength and ductility levels as the standard ageing of mill-annealed material. This is promising since both grain boundary γ′ and a bi-modal intragranular γ′ distribution can be used to tailor the mechanical properties to suit specific applications. The yield strength of all three conditions could be accurately predicted by a unified precipitation strengthening model

    Time- and cycle-dependent crack propagation in Haynes 282

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    Haynes 282 is a promising superalloy candidate for several high-temperature applications in both aero and land-based gas turbine engines. To study the crack growth behaviour under time-dependent conditions relevant to such applications, a test program was carried out at room temperature up to 700 °C with conditions ranging from pure cyclic to sustained tensile loading. At 650 °C and high stress intensity factors the crack growth was fully time-dependent for dwell-times of 90 s and longer. At lower stress intensities, the behaviour was mainly controlled by the cyclic loading, even under dwell conditions. The behaviour under dwell-fatigue conditions was well described by a liner superposition model. The main crack growth occurred transgranularly at room temperature and there was a transition in cracking behaviour from cycle dependent transgranular growth to time-dependent intergranular propagation at dK=45 MPa m^0.5 for the high temperature tests. No effect of cyclic frequency could be observed at room temperature, and at lower frequencies the crack growth rate increased with temperature

    Crack Growth Studies in a welded Ni-base superalloy

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    It is well known that the introduction of sustained tensile loads during high-temperature fatigue (dwell-fatigue) significantly increases the crack propagation rates in many superalloys. One such superalloy is the Ni-Fe based Alloy 718, which is a high-strength corrosion resistant alloy used in gas turbines and jet engines. As the problem is typically more pronounced in fine-grained materials, the main body of existing literature is devoted to the characterization of sheets or forgings of Alloy 718. However, as welded components are being used in increasingly demanding applications, there is a need to understand the behavior. The present study is focused on the interaction of the propagating crack with the complex microstructure in Alloy 718 weld metal during cyclic and dwell-fatigue loading at 550 °C and 650 °C

    Room temperature plasticity in sub-micrometer thermally grown oxide scales

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    Thermally grown oxides (TGOs) are generally considered to be brittle, capable of sustaining very limited plastic deformation before fracture. As they are prone to exhibit different forms of defects, the fracture toughness, typically measured to be some 1–2 MPa m1/2 [1], is typically reached well before sufficiently high stresses to induce plasticity can be applied [2]. This is particularly true at room temperature, where possible low-stress thermally activated creep mechanisms are suppressed. However, the occurrence of plasticity in e.g. Al2O3 single crystals at room temperature can occur for samples in the micrometer range [3]. Most measurements of the deformation of TGOs have been made on relatively thick scales, (\u3e1 micrometer), which are limited by the fracture originating from inherent defects. Furthermore, the studies have been limited in resolution and sensitivity, as the scales were adherent to the substrates and tested as a composite. Recently, micro-mechanical testing has been introduced as a method to evaluate mechanical behavior of TGOs on a ferritic/martensitic steel [4], where micro-cantilever bending was used to test specimen extracted from different layers in a 5–10 micrometers thick oxide. Still, the cantilever cross-section was typically several micrometers, and the very similar fracture stresses for notched and un-notched cantilevers seems to indicate that the deformation is still limited by inherent defects. Please click Additional Files below to see the full abstract

    Deformation and Failure of OFHC Copper under high strain rate shear compression

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    Hat-shaped specimen geometries were developed to generate high strain, high-strain-rates deformation under prescribed conditions. These geometries offer also the possibility to investigate the occurrence of ductile rupture under low or negative stress triaxiality, where most failure models fail. In this work, three tophat geometries were designed, by means of extensive numerical simulation, to obtain desired stress triaxiality values within the shear region that develops across the ligament. Material failure was simulated using the Continuum Damage Model (CDM) formulation with a unilateral condition for damage accumulation and validated by comparing with quasi-static and high strain rate compression tests results on OFHC copper. Preliminary results seem to indicate that ductile tearing initiates at the specimen corner location where positive stress triaxiality occurs because of local rotation and eventually propagates along the ligament

    Microscale fracture of chromia scales

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    High temperature materials such as superalloys rely on the formation of a protective surface oxide scale for prevention of corrosion. Such materials undergo periods of varying thermal and mechanical loads during operation, which can lead to cracking of the surface oxide. This exposes the material to corrosion, and can also act as stress concentrations, which affects the life of the underlying material. It is therefore necessary to consider the mechanical integrity of these scales while estimating material life. Several models have been developed in which fracture mechanics is utilized to estimate failure. But there is a lack of data such as fracture strains and elastic modulus for oxide scales. Conventional mechanical testing methods such as tensile and bending tests have been modified to obtain mechanical data, but it mainly applies to thick oxide scales (several µm thick). These methods are also limited with respect to isolating substrate and residual stress effects. For advanced materials, where the oxide formation kinetics are low, new methods are required in order to assess the mechanical properties. Please click Additional Files below to see the full abstract
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