The metastable phase Ni2Mo and the initial stages of ordering in NiMo alloys

Das, Sanjib; Thomas, G.

doi:10.1002/pssa.2210210119

Cited by 96 publications

(22 citation statements)

References 14 publications

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“…Dark-field images in the SRO spots were first shown by Ruedl, Delavignette & Amelinckx (1968) to be spotty and attributed to the occurrence of microdomains of the different orientation variants. Later this was confirmed and discussed by a number of authors (Moss & Clapp, 1968;Okamoto & Thomas, 1971;Das & Thomas, 1974;Chakravarti, Starke, Sparks & Williams, 1974).…”

Section: The Ni-mo Systemmentioning

confidence: 68%

A cluster model for the transition from the short-range order to the long-range order state in f.c.c. based binary systems and its study by means of electron diffraction

Ridder¹,

Tendeloo²,

Amelinckx³

1976

Acta Cryst Sect A

169

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The 'transition' state in binary, f.c.c, based systems is assumed to be characterized by the repetition of interpenetrating polyhedral clusters of atoms occupying lattice sites and having the macroscopic composition. Its mathematical formulation leads to relations between the short-range order (SRO) coefficients, which in turn impose conditions on the distribution in reciprocal space of the diffuse intensity as observed in electron diffraction patterns. It follows that for a given cluster type the diffuse intensity can only differ from zero along certain surfaces or curves. The effect of deviations from the ideal composition of the clusters is briefly discussed. The theory allows an explanation of available diffraction data on certain binary alloys in the initial stages of ordering i.e. in the 'transition' state between the SRO state and the long-range order (LRO) state.

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Section: The Ni-mo Systemmentioning

confidence: 68%

A cluster model for the transition from the short-range order to the long-range order state in f.c.c. based binary systems and its study by means of electron diffraction

Ridder¹,

Tendeloo²,

Amelinckx³

1976

Acta Cryst Sect A

169

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“…1). The characteristics of this phase were given by Das & Thomas (1974) and Kumar & Vasudevan (1996). The crystal structure of the Ni 2 Mo phase can be described in terms of f.c.c.…”

Section: Resultsmentioning

confidence: 99%

Influence of plastic deformation and prolonged ageing time on microstructure of a Haynes 242 alloy

Dymek

Wróbel

Dollár

et al. 2006

Journal of Microscopy

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SummaryThe material used in this study was a commercial HAYNES® alloy 242™ with a nominal composition of Ni-25% Mo-8% Cr (in wt.%). In the standard heat treatment, the 242 alloy is annealed at a temperature between 1065 and 1095 °C and then water quenched. The ageing treatment is carried out at 650 °C for 24 h in order to develop the long-range-order strengthening. The alloy in the conventionally aged condition was additionally cold rolled to 50% reduction in thickness and subsequently subjected to prolonged ageing at 650 °C for 4000 h. The enhanced diffusion resulted in the decomposition of the Ni 2 (Mo,Cr) metastable phase into the stable Ni 3 Mobased phase. The presence of the new stable phase increased the yield and tensile strengths but deteriorated the ductility of the alloy at both room and 650 °C temperatures.

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“…(2) n ) and N 3 = c(1Ϫh (1) n )where h (1) n and h (2) n are the order parameters belonging to ͗1 1 2 0͘ and ͗100͘ wave vectors, respectively. The internal energy is given by …”

Section: ϫN(r(p)))ln(1ϫn(r(p)))]mentioning

confidence: 99%

“…Some unique features of ordering transformation in this system have attracted the attention of several research groups. An extensive amount of research work [2][3][4] has been dedicated to understand the behavior of phase transformations that occur in this system [5,6]. There have been a number of studies on the ordering of Ni 4 Mo and Ni 3 Mo based alloys.…”

Section: Introductionmentioning

confidence: 99%

A first-principles thermodynamic approach to ordering in Ni-Mo alloys

et al. 2001

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Abstract-There is a competition between several face centered cubic (FCC)-based ordered inter-metallic phases in Ni-Mo alloys containing 8-33 at% Mo. The transformation behavior of these alloys in terms of ordering instabilities has been studied. First-principles tight-binding-linear muffin-tin orbital (TB-LMTO) method coupled with augmented space recursion (ASR) in conjunction with orbital peeling (OP) technique has been employed to extract the concentration dependent effective pair interactions. Further, the mean-field statistical mechanics based static concentration wave (SCW) model has been used to determine the free energies of these ordered phases as functions of temperature, composition and order parameter. This ASR-OP-SCW approach, applied to Ni-Mo alloy system, gives the correct ground state stability sequence as observed experimentally. Furthermore, it has been shown that such an approach can be used to study the complex transformation behavior involving several competing superstructures as well as competing first order and second order ordering processes.

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The metastable phase Ni2Mo and the initial stages of ordering in NiMo alloys

Cited by 96 publications

References 14 publications

A cluster model for the transition from the short-range order to the long-range order state in f.c.c. based binary systems and its study by means of electron diffraction

A cluster model for the transition from the short-range order to the long-range order state in f.c.c. based binary systems and its study by means of electron diffraction

Influence of plastic deformation and prolonged ageing time on microstructure of a Haynes 242 alloy

A first-principles thermodynamic approach to ordering in Ni-Mo alloys

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