Journal ArticleDOI
Development and validation of a processing map for zirconium alloys
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TLDR
In this paper, a simple instability condition based on the Ziegler's continuum principles is extended for delineating the regions of unstable metal flow/occurrence of fracture or defects, utilizing the flow stress data of Zr-2.5Nb-0.5Cu.Abstract:
For the development of processing maps to zirconium alloys, a simple instability condition based on the Ziegler's continuum principles as applied to large plastic flow is extended for delineating the regions of unstable metal flow/occurrence of fracture or defects, utilizing the flow stress data of Zr-2.5Nb-0.5Cu. An attempt is made to fit the measured flow stress data in a constitutive equation, useful in the finite element process models. Instability maps at different strain levels were superimposed while delineating the unstable regions in the processing maps. This phenomenon takes into account the dependence of strain rate sensitivity and strain hardening coefficient of the material on the plastic instability during hot deformation. The applicability of the developed processing map has been examined by comparing with the reported microstructural observations of the deformed compression specimens of various zirconium alloys. It is found that the processing map is practically usable in the real fabrication process for the zirconium alloys.read more
Citations
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Study on the hot deformation behavior of TC4-DT alloy with equiaxed α+β starting structure based on processing map
TL;DR: In this paper, the authors investigated the hot deformation behavior of TC4-DT alloy with an initial equiaxed α+β structure by conducting isothermal hot compression test in the deformation temperature range of 930-1020°C and strain rate range of 0.001-10 s −1 with the maximum height reduction of 60%.
Journal ArticleDOI
Hot deformation behavior of Zr-2.5Nb alloy: A comparative study using different materials models
Kuldeep K. Saxena,S. Sonkar,Vivek Pancholi,Gajanan P. Chaudhari,Dinesh Srivastava,G.K. Dey,S.K. Jha,N. Saibaba +7 more
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.
Journal ArticleDOI
Hot workability and microstructure control in Co20Cr15W10Ni cobalt-based superalloy
TL;DR: In this article, hot isothermal compression tests were conducted on Cobalt-based superalloy Co 20Cr 15W 10Ni using a thermo-mechanical simulator to study the hot workability and microstructure evolution over a wide range of temperatures and strain rates.
Journal ArticleDOI
Development and validation of a processing map for Aermet100 steel
TL;DR: In this article, a processing map of Aermet100 steel was developed based on a simple instability condition applicable to a general flow stress versus strain rate curve at any strain and temperature.
Journal ArticleDOI
Physical Simulation of Hot Deformation of Low-Carbon Ti-Nb Microalloyed Steel and Microstructural Studies
TL;DR: In this article, the average apparent activation energy for hot deformation was obtained as 359 kJ/mol using sinh type constitutive equation, and safe domains of strain, strain rate, and temperature for hot working of a 0.052 pct Ti microalloyed steel have been identified.
References
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Book
Deformation-Mechanism Maps: The Plasticity and Creep of Metals and Ceramics
H.J. Frost,Michael F. Ashby +1 more
TL;DR: Deformation-mechanism maps: the plasticity and creep of metals and ceramics as discussed by the authors, Deformation-Mechanism Maps of metal deformation: the deformation and the creep of metal and ceramic.
Journal ArticleDOI
Plastic instability under plane stress
TL;DR: In this paper, conditions for instability of plastic strain under plane stress for a material conforming to the Mises-Hencky yield condition and strain-hardening according to a unique relationship between root-mean-square values of shear stress (q) and incremental strain (δψ).
Journal ArticleDOI
Modeling of dynamic material behavior in hot deformation: Forging of Ti-6242
Y. V. R. K. Prasad,Y. V. R. K. Prasad,H. L. Gegel,S. M. Doraivelu,J. C. Malas,J. T. Morgan,K. A. Lark,D. R. Barker +7 more
TL;DR: In this article, a new method of modeling material behavior which accounts for the dynamic metallurgical processes occurring during hot deformation is presented, which considers the workpiece as a dissipator of power in the total processing system and evaluates the dissipated power co-contentJ = ∫o σ e ⋅dσ from the constitutive equation relating the strain rate (e) to the flow stress (σ).
Journal ArticleDOI
Theory of the tensile test
TL;DR: In this paper, the tensile test is re-examined with special attention to the influence of strain rate sensitivity of the flow stress, and explicit formulae are deduced for the measured variables of the test in terms of the phenomenological parameters of the material.
Journal ArticleDOI
Time, structure, and fluctuations.
TL;DR: It is shown that nonequilibrium may become a source of order and that irreversible processes may lead to a new type of dynamic states of matter called "dissipative structures" and the thermodynamic theory of such structures is outlined.