scispace - formally typeset
Search or ask a question
Journal ArticleDOI

Effect of strain rate and test temperature on superplasticity of a Zr–2.5 wt% Nb alloy

TL;DR: In this article, a Zr-2.5 wt% Nb pressure tube alloy was deformed at strain rates (e ) of 3.2 × 10−4−2 s−1 and test temperatures (T) of 625-800°C to investigate the nature of stress-strain curves and the optimum condition for superplasticity.
About: This article is published in Journal of Nuclear Materials.The article was published on 1999-07-01. It has received 13 citations till now. The article focuses on the topics: Superplasticity & Strain rate.
Citations
More filters
Journal ArticleDOI
TL;DR: In this article, three models, namely Dynamic Materials Model (DMM), modified dynamic materials model (MDMM) and α-parameter, were used to develop processing maps of Zr-2.5Nb alloy.

37 citations

Journal ArticleDOI
TL;DR: In this paper, the effect of grain size on superplastic deformation in Zr −2.5% Nb was studied by constructing processing maps, which depict the variation of strain rate sensitivity with temperature and strain rate.
Abstract: The effect of grain size on superplastic deformation in Zr–2.5 wt.%Nb was studied by constructing processing maps (which depict the variation of strain rate sensitivity with temperature and strain rate) in the temperature range of 650–830 °C and strain rate range of 5 × 10 −6 to 2 × 10 −3 s −1 . The occurrence of superplastic domain with respect to temperature and strain rate was identified for three grain sizes (4, 10 and 16 μm). The 4 μm grain size material exhibited a domain centered around 800 °C and 10 −4 s −1 , exhibiting a ductility of 700%. With increasing grain size the domain shifts to higher temperatures and lower strain rates. A detailed characterization of deformed microstructure revealed equiaxed grain structure (curved boundaries) with considerable grain growth within the superplastic domain. Creep equation was used to evaluate the parameters of superplastic deformation, which resulted in activation energy of 125 kJ/mol and a grain size exponent of 1.6. The accommodation mechanism for superplastic deformation was deduced to be either non-conservative jog motion or grain boundary migration, with the rate controlling step for both being the grain boundary diffusion of Zr and Nb in β phase.

31 citations

Journal ArticleDOI
Z.N. Yang1, F.C. Zhang1, L. Qu1, Zhigang Yan1, Y.Y. Xiao1, R.P. Liu1, X.Y. Zhang1 
TL;DR: In this article, the formation of duplex microstructure in Zr-2.3Nb alloys at a temperature range of 850-925°C, its plastic behaviour at various strain rates and the accommodation of each phase in each phase during the tensile deformation process were investigated thoroughly.

31 citations

Journal ArticleDOI
TL;DR: In this article, two new approaches are proposed for developing processing maps to predict domains of high dissipation efficiency, which are corroborated by microstructural analysis using electron backscattered diffraction (EBSD).

29 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used tensile tests carried out in the temperature range from room temperature to 800 °C using the samples taken out from a single pressure tube have been used to develop correlations for characterizing the strength parameters' variation as a function of axial location along length of the tube and the test temperature.

17 citations

References
More filters
Book
01 Jan 2009
TL;DR: In this paper, an overview of mechanical behavior is presented, including Elastic Behavior, Dislocations, Plastic Deformation in Single and Polycrystalline Materials, Strengthening of Crystalline materials, Composite Materials, Fracture Mechanics, Toughening Mechanisms and the Physics of Fracture.
Abstract: 1 Overview of Mechanical Behavior 2 Elastic Behavior 3 Dislocations 4 Plastic Deformation in Single and Polycrystalline Materials 5 Strengthening of Crystalline Materials 6 Composite Materials 7 High-Temperature Deformation of Crystalline Materials 8 Deformation of Noncrystalline Materials 9 Fracture Mechanics 10 Toughening Mechanisms and the Physics of Fracture 11 High-Temperature 12 Fatigue of Engineering Materials 13 Embrittlement 14 Cellular Solids

1,201 citations

Journal ArticleDOI
TL;DR: The relationship between stress and strain rate is often sigmoidal in superplastic materials, with a low strain rate sensitivity at low and high strain rates (regions I and III, respectively) and a high strain rate sensitive at intermediate strain rate (region II) where the material exhibits optimal super-plasticity as discussed by the authors.
Abstract: The relationship between stress and strain rate is often sigmoidal in superplastic materials, with a low strain rate sensitivity at low and high strain rates (regions I and III, respectively) and a high strain rate sensitivity at intermediate strain rates (region II) where the material exhibits optimal superplasticity This relationship is examined in detail, with reference both to the conflicting results reported for the Zn-22 pct Al eutectoid alloy and to the significance of the three regions of flow

378 citations

Journal ArticleDOI
TL;DR: There are four distinct types of fracture in superplastic materials: failure by quasistable plastic flow, failure by necking, cavitation failure, and quasibrittle failure as discussed by the authors.
Abstract: There are four distinct types of fracture in superplastic materials: failure by quasistable plastic flow, failure by necking, cavitation failure, and quasibrittle failure. The characteristics of these four types are described with reference to experimental examples. Maximum elongation occurs in a superplastic material when it pulls out to a fine wire in quasi stable flow. It is demonstrated that there are two basic requirements for this type of flow: (a) a suppression of localized (but not diffuse) necking, and (b) a suppression of significant cavity interlinkage (but not necessarily of cavity nucleation and growth).

126 citations

Journal ArticleDOI
TL;DR: The microstructural aspects of the superplastic phenomenon are reviewed in this article, where experimental results of a very large number of investigations are critically analysed in the context of: grain shape and size; grain growth; grain boundary sliding and migration, grain rotation and rearrangement; diffusion and dislocation activity.
Abstract: The microstructural aspects of the superplastic phenomenon are reviewed. The experimental results of a very large number of investigations are critically analysed in the context of: grain shape and size; grain growth; grain boundary sliding and migration, grain rotation and rearrangement; diffusion and dislocation activity. It is shown, that in spite of often conflicting evidence in the literature, a common pattern of microstructural behaviour emerges for all the materials and conditions investigated to date.

124 citations