Precipitation studies on alloys from the system copper chromium zirconium

The precipitation reactions occurring in a series of copper-based alloys selected from the system copper-chromium-zirconium have been studied by resistometric and metallographic techniques. A survey of the factors influencing the development of copper-based alloys for high strength, high conductivity applications is followed by a more general review of contemporary materials, and illustrates that the most promising alloys are those containing chromium and zirconium. The few systematic attempts to study alloys from this system have been collated, discussed, and used as a basis for the selection of four alloy compositions viz:- Cu - 0.4% Cr Cu - 0.24. Zr Cu - 0. 3% Cr - 0.1% Zr Cu - 0.2% Cr - 0.2% Zr A description of the experimental techniques used to study the precipitation behaviour of these materials is preceeded by a discussion of the currently accepted theories relating to precipitate nucleation and growth. The experimental results are presented and discussed for each of the alloys independently, and are then treated jointly to obtain an overall assessment of the way in which the precipitation kinetics, metallography and mechanical properties vary with alloy composition and heat treatment. The metastable solid solution of copper-chromium is found to decompose by the rejection of chromium particles which maintain a coherent interface and a Kurdjumov-Sachs type crystallographic orientation relationship with the copper matrix. The addition of 0.1% zirconium to the alloy retards the rate of transformation by a factor of ten and modifies the dispersion characteristics of the precipitate without markedly altering the morphology. Further additions of zirconium lead to the growth of stacking faults during ageing, which provide favourable nucleation sites for the chromium precipitate. The partial dislocations bounding such stacking faults are also found to provide mobile heterogeneous nucleation sources for the precipitation reactions occurring in copper-zirconium.

Intragranular nucleation of austenite

The mechanism of intragranular nucleation of austenite in a duplex stainless steel (Fe-23.1 Cr-6.1 Ni-3.1 Mo-O.165 N-0.017 C, wt.%) weld metal and heat-affected zone (HAZ) has been examined. In the weld metal the acicular austenite is found to nucleate intragranularly on inclusions and subsequent plates form sympathetically resulting in a fine interlocked microstructure. Austenite plates adopt the Kurdjumov-Sachs orientation relationship with the ferrite matrix and grow with diffusion-controlled mechanism as evident from partitioning of substitutional alloying elements. At least one set of fine intrinsic dislocations on the austenite/ferrite interphase interfaces is observed suggesting that the boundaries are semi-coherent. The high cooling rates involved in the HAZ result in a supersaturated ferrite matrix where precipitation of intragranular austenite occurs as a result of reheating associated with subsequent passes. Austenite particles in the HAZ nucleate preferentially away from gain boundary austenite allotriomorphs indicating that intragranular precipitation is favoured by the supersaturated matrix.

Strengthening mechanisms in nanostructured copper/304 stainless steel multilayers

Nanostructured Cu/304 stainless steel (SS) multilayers were prepared by magnetron sputtering. 304SS has a face-centered-cubic (fcc) structure in bulk. However, in the Cu/304SS multilayers, the 304SS layers exhibit the fcc structure for layer thickness of =5 nm in epitaxy with the neighboring fcc Cu. For 304SS layer thickness larger than 5 nm, body-centered-cubic (bcc) 304SS grains grow on top of the initial 5 nm fcc SS with the Kurdjumov-Sachs orientation relationship between bcc and fcc SS grains. The maximum hardness of Cu/304SS multilayers is about 5.5 GPa (factor of two enhancement compared to rule-of-mixtures hardness) at a layer thickness of 5 nm. Below 5 nm, hardness decreases with decreasing layer thickness. The peak hardness of fcc/fcc Cu/304SS multilayer is greater than that of Cu/Ni, even though the lattice-parameter mismatch between Cu and Ni is five times greater than that between Cu and 304SS. This result may primarily be attributed to the higher interface barrier stress for single-dislocation transmission across the {111} twinned interfaces in Cu/304SS as compared to the {100} interfaces in Cu/Ni.

The relationship between mechanical properties, preffered orientation and press forming behaviour of copper and 70/30 brass

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Goal orientation and its relationship to the business family, and family business performance, within the UK’s family owned and managed mid-sized businesses

Mid-Sized Businesses (MSBs) are defined by the Department for Business, Innovation and Skills (BIS) as having a sales turnover of between £25 million and £500 million. A key gap in family firm/business research and literature to date is, understanding the role and importance of non-financial objectives (such as family harmony, tradition and business longevity), and the role the family plays in creating a wide set of business performance objectives (both financial and non-financial) in these businesses. This dissertation contributes to filling this knowledge gap by drawing on Family Systems Theory applied in a business context, and within an overarching Resource Based View (RBV) of the firm.

Countering the trend towards careerist orientation in the age of downsizing:test of a social exchange model

Predicated on the assumption that employee careerist orientation resulting from organizational actions to cut costs constitutes a potential threat to their long-term profitability and success, this study proposed and tested a social exchange model of careerist orientation in the People's Republic of China. Specifically, it was hypothesized that organizational justice and career growth opportunities will be related to careerist orientation, but the relationship will be mediated by trust in employer. Structural equation modeling results provided support for the model. Trust in organization fully mediated the relationship between careerist orientation and its antecedents.

Guest editorial: Market orientation and service firm performance - a research agenda

The service sector is an increasingly important source of job creation and economic wealth, and accounts for more than 75 per cent of the GDP of many developed economies. Yet there has been surprisingly little research into the relationship between market orientation and service firm performance. This editorial reviews the major research themes relating to market orientation and service firm performance and suggests an agenda for future research to improve understanding of this important marketing and management issue.

Does business environment matter to the development of a market orientation?

Developing a market orientation is one of the key issues in market-orientation research. In this study, based on a survey of top managers from 143 Chinese hotels and 72 travel services—two tourism sectors with distinctly different business environments—we explore the effects of environmental conditions on the development of market orientation. In particular we examine whether environmental conditions have a direct impact on the level of market orientation or whether they moderate the relationship between market orientation and its antecedents. We find that the effectiveness of top management emphasis varies under different environmental conditions but that the impact of other antecedents is not influenced by environmental conditions.

An examination of the consequences of market orientation in China

Recent literature suggests that the relationship between market orientation and business performance may be moderated by the nature of the external environment. While the conceptual arguments for such a relationship are well established, empirical evidence on the precise nature of this link has been both limited and ambiguous. The current paper provides further evidence on the nature of the links between market orientation, the environment and performance through a comparative analysis of two business sectors in China with distinctively different competitive environments. The results indicate that market orientation's impact on business performance is positive regardless of environmental conditions. However, the environment is found to moderate the relationship between market orientation and customer satisfaction. Finally, the study provides evidence that market orientation also has positive impacts on power in distribution channels and corporate social responsibility.

Morningness-eveningness orientation and attitude change:evidence for greater systematic processing and attitude change at optimal time-of-day

This study examines the relationship between morningness-eveningness orientation and time-of day on attitude change, and tests the hypothesis that people will be more persuaded when tested at their optimal time-of-day (i.e., morning for M-types and evening for E-types) than non-optimal time-of-day (i.e., evening for M-Types and morning for E-types). Two hundred and twenty participants read a message that contained either strong vs. weak quality counter-attitudinal arguments (anti-voluntary euthanasia) in the morning (9.00. a.m.) or in the evening (7.00. p.m.). When tested at their respective optimal time-of-day (for both M- and E-types) there was a reliable difference in attitude change between the strong vs. weak messages (indicating message processing had occurred) while there was no difference between strong vs. weak messages when tested at their non-optimal time-of-day. In addition, the amount of message-congruent thinking mediated the attitude change. The results show that M- and E-types pay greater attention to and elaborate on a persuasive message at their optimal time-of-day, and this leads to increased attitude change, compared to those tested at their non-optimal time-of-day. © 2012.

The relationship between fracture toughness and microstructure in titanium alloys

Linear Elastic Fracture Mechanics has been used to study the microstructural factors controlling the strength and toughness of two alpha-beta, titanium alloys. Fracture toughness was found to be independent of orientation for alloy Ti/6A1/4-V, but orientation dependent for IMI 700, bend and tension specimens giving similar toughness values. Increasing the solution temperature led to the usual inverse relationship between strength and toughness, with toughness becoming a minimum as the beta transus was approached. The production of a double heat treated microstructure led to a 100% increase in toughness in the high strength alloy and a 20% increase in alloy Ti/6A1/4V, with little decrease in strength. The double heat treated microstruoture was produced by cooling from the beta field into the alpha beta field, followed. by conventional solution treatment and ageing. Forging above the beta transus led to an increase in toughness over alpha beta forging in the high strength alloy, but had little effect on the toughness of Ti/6A1/4V. Light and electron microscopy showed that the increased toughness resulted from the alpha phase being changed from mainly continuous to a discontinuous platelet form in a transformed beta matrix. Void formation occurred at the alpha-beta interface and crack propagation was via the interface or across the platelet depending on which process required the least energy. Varying the solution treatment temperature produced a varying interplatelet spacing and platelet thickness. The finest interplatelet spacing was associated with the highest toughness, since a higher applied stress was required to give the necessary stress concentration to initiate void formation. The thickest alpha platelet size gave the highest toughness which could be interpreted in terms of Krafftt's "process zone size" and the critical crack tip displacement criterion by Hahn and Rosenfield from an analysis by Goodier and Field.

Organizational learning orientation profile and implications for strategic planning capacity

Theory development on the relationship between strategic planning and organizational performance has focussed on largely discrete examinations of dependent and independent variables. While the literature has examined the impact of organizational learning on strategic planning, no holistic empirical approaches have been employed in order to fully explore the inter-play between these important constructs. This paper addresses the cited limitations in both the strategic planning and organizational performance literatures by creating profiles of organizational learning and strategic planning capacity using a configuration theory-based approach. The organizational learning orientation profiles (OLOPs) created of prospector, disseminator, interpretative and memory, contribute to theory development regarding the relationship of strategic planning and organizational learning. The theory developed provides insights that have not been previously reported.