Effect of thermomechanical parameters on the critical strain for ultrafine ferrite formation through hot torsion testing

A C–Mn–V steel was used to study ultrafine ferrite formation (1–3 μm) through dynamic strain-induced transformation (DSIT) using hot torsion experiments. A systematic study determined the critical strain for the start of DSIT (C,DSIT), although this may not lead to a fully ultrafine microstructure. Therefore, the strain to produce an ultrafine ferrite (UFF) as final microstructure (C,UFF) during deformation was also determined. In addition, the effect of thermomechanical parameters such as deformation temperature, prior austenite grain size, strain rate and cooling rate on C,DSIT and C,UFF has been evaluated. DSIT ferrite nucleated on prior austenite grain boundaries at an early stage of straining followed by intragranular nucleation at higher strains. The prior austenite grain size affected the distribution of DSIT ferrite nucleation sites at an early stage of transformation and the subsequent coarsening behaviour of the grain boundary and intragranular ferrite grains during post-deformation cooling. Also, C,DSIT and C,UFF increased with an increase in the prior austenite grain size and deformation temperature. The post-deformation cooling had a strong effect not only on C,UFF but also the UFF microstructure (i.e. final ferrite grain size and second phase characteristics).

A review of employment relations theories and their application

New developments in the industrial relations and human resource management have moved management and employee bargaining down to the level of the firm. In doing so they have generated a growing level of interest in the conduct of employment relations, not just at the level of specialist managers, who have traditionally had the responsibility for dealing with issues in this area, but across management as a whole. There is thus a growing need for managers to place more emphasis on achieving a greater symmetry between commercial objectives and employment practices. This paper looks at the predicates of managerial authority and its legitimacy, and how personal assumptions and value systems (i.e., ‘frames of reference’) held by managers can predispose them to view the nature of work and workplace relations in particular ways. The paper also presents
and aligns a range of contemporary theories within the province of such systems, with the aim being to show how judgements made about the worth or otherwise of a given range of theories are inevitably shaped by the type of value system and set of assumptions one holds towards the
world of work. The paper concludes by offering a practical guide to managers on how to evaluate their own assumptions and value systems when applying the noted theories and concepts to real world circumstances. In doing so, the paper provides a tool kit of theories and concepts that should allow managers to avoid engaging in workforce management practices that are either illconceived or based on intuitive premises.

Formation of a W-25%Cu nanocomposite during high pressure torsion

A coarse-grained W–25%Cu composite is subjected to high pressure torsion (HPT) at room temperature, 200 °C, and 400 °C, to different very large strains. The evolution of microstructure with increasing strain is investigated. It is shown that the HPT causes a strong refinement of W particles. No significant influence of the deformation temperature on the microstructure is revealed at small strains (64). A strong effect of the HPT temperature on the microstructure is found at larger strains (>64). It is demonstrated that the HPT can be successfully used to fabricate a W–25%Cu nanocomposite.

Deformation behaviour of a cylinder under simultaneous compression and torsion

A number of experiments involving the compression of an Aluminum cylinder with concurrent die rotation were carried out. Two important features were observed: one was that die rotation reduced the degree of bulging and the other was that the compression load decreased. An upper bound analysis with a velocity field consisting of a compound exponential cusp representation was utilized to obtain an approximate analytical solution in a closed form. The theoretical result reproduced the reduction in bulging severity with die rotation as well as the changes in compression pressure.

Should we save or should we consume? Linking growth theories and the Keynesian models

In major economic growth theories, high saving rate gives rise to high level of output per capita. But in Keynesian economics, high saving rate causes low consumption and will lead the economy into recession. Students may ask, "For the well-being of an economy, should we save or should we consume?" In most of the intermediate macroeconomics textbooks, economic growth and Keynesian economics are taught in separate chapters; and in many cases, these chapters are not even successive to each other. There lacks a continuity between the long run and short run models. This paper builds a bridge between growth theories and Keynesian models. It links the Solow diagram and the IS-LM curves and depicts the short run and long run implications of a change in the saving rate.

Predicting consumer innovative behavior using alternative theories and likelihood measures: a longitudinal study

This paper reports on a longitudinal study of consumers, where two dominant theories that purport to predict innovative behavior are applied and compared directly, using a methodology suggested as ideal by past researchers. Predictions made prior to launch were then evaluated against multiple measures of purchase likelihood, and against actual adoption behavior up to 12 months after launch. The results of this study suggest that perceptions of the innovations characteristics (PIC) predicted the selfreported likelihood of adoption better than the Domain Specific Innovativeness (DSI) scale, a personality-based measure. Prediction of actual adoption was largely inaccurate and both theories massively over predicted adoption levels, however the DSI scale was slightly more accurate. The conclusions here are that no one theory could make adequate predictions of behavior, that purchase likelihood measures are a poor substitute for measuring actual behavior but that purchase probability scales should be used more often in adoption research.

Applications of cognitive theories to children's fire safety education

Children under five have the highest rate of fire-related accidents (Australian Institute of Health and Welfare, 2001). It is therefore essential to develop effective fire safety education programs to prevent casualties due to a fire. At present, there are fire education programs conducted across Australia for primary school children. However, it is vital that these programs get their message across to the children in the most efficient manner to help children retain the information. The present study evaluated the effectiveness of the 'Fire Ed' program conducted in Victoria and assessed the retention of fire safety information in children in preparatory and Grade five levels. The findings suggest that the information is not retained over long periods of time. Suggestions are made to provide fire safety education in line with
theories of cognitive development to make it more effective.

Integrating job stress and social exchange theories to predict employee wellbeing

This research examines the organizational characteristics that contribute to employee wellbeing in public sector agencies that have undergone substantial organizational change. Two studies were undertaken, the first involving 2,466 police officers working in a statebased law enforcement agency, whereas the second comprised 1,010 occupationally diverse employees working in a State Government authority. The research was guided by a theoretical framework that begins with a model underpinning many large-scale job stress investigations—the job strain model (JSM)—and is expanded to incorporate widely used social exchange variables (i.e., psychological contract breach and organizational fairness). The results of hierarchical regression analyses from both studies confirm the value of the JSM. There was also strong support for extending the JSM to include the breach and fairness variables; however, proposed interactions between job demands and organizational fairness failed to add to the explanatory value of the model. The implications of these results particularly for public sector organizations that have undergone extensive reforms consistent with New Public Management are discussed.

Effect of process variables on formation of dynamic strain induced ultrafine ferrite during hot torsion testing

Ultrafine grain sizes were produced using hot torsion testing of a 0.11C-1.68Mn-0.20Si (wt-%) steel, with ultrafine ferrite (<1 µm) nucleating intragranularly during testing by dynamic strain induced transformation. A systematic study was made of the effect of isothermal deformation temperature, strain level, strain rate, and accelerated cooling during deformation on the formation of ultrafine ferrite by this process. Decreasing the isothermal testing temperature below the Ae₃ temperature led to a greater driving force for ferrite nucleation and thus more extensive nucleation during testing; the formation of Widmanstätten ferrite prior to, or early during, deformation imposed a lower temperature limit. Increasing the strain above that where ferrite first began 0.8 at 675C and a strain rate of 3 s¯¹ increased the intragranular nucleation of ferrite. Strain rate appeared to have little effect on the amount of ferrite formed. However, slower strain rates led to extensive polygonisation of the ferrite formed because more time was available for ferrite recovery. Accelerated cooling during deformation followed by air cooling to room temperature led to a uniform microstructure consisting of very fine ferrite grains and fine spherical carbides located in the grain boundaries regions. Air cooling after isothermal testing led to carbide bands and a larger ferrite grain size.

The production of ultrafine ferrite during hot torsion testing of a 0.11 Wt Pct C steel

Ultrafine ferrite grain sizes were produced in a 0.11C-1.6Mn-0.2Si steel by torsion testing isothermally at 675 °C after air cooling from 1250 °C. The ferrite was observed to form intragranularly beyond a von Mises equivalent tensile strain of approximately 0.7 to 0.8 and the number fraction of intragranular ferrite grains continued to increase as the strain level increased. Ferrite nucleated to form parallel and closely spaced linear arrays or “rafts” of many discrete ultrafine ferrite grains. It is shown that ferrite nucleates during deformation on defects developed within the austenite parallel to the macroscopic shear direction (i.e., dynamic strain-induced transformation). A model austenitic Ni-30Fe alloy was used to study the substructure developed in the austenite under similar test conditions as that used to induce intragranular ferrite in the steel. It is shown that the most prevalent features developed during testing are microbands. It is proposed that high-energy jogged regions surrounding intersecting microbands provide potential sites for ferrite nucleation at lower strains, while at higher strains, the walls of the microbands may also act as nucleation sites.