Flow transitions and flow localization in large-strain deformation of magnesium alloy

Date

2016-04-06

Author

Sagapuram, Dinakar
Efe, Mert
Trumble, Kevin P.
Chandrasekar, Srinivasan

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

278
views

0
downloads

Understanding transitions from homogeneous to localized flow, and mechanisms underlying flow localization, is of paramount importance for deformation processing of magnesium. In this study, a shear based deformation method is utilized for imposing large strains (similar to 1), under controllable strain rates (10-10(5)/s) and temperatures (80-300 degrees C), in order to examine flow patterns in a magnesium alloy. Based on microstructure characterization, deformation twinning is suggested to contribute to the localized flow at temperatures below 200 degrees C and at low strain rates. The transition from the localized to homogeneous flow with increasing temperature is due to reduction in twinning activity, and enhanced strain-rate sensitivity. At constant temperature, an increase in the strain rate decreases the propensity for flow localization. A model is presented for characterizing the maximum uniform strain as a function of temperature and deformation state (simple shear, plane-strain compression). The model incorporates temperature-sensitive microstructural changes and flow properties of magnesium into a classical framework to capture the flow localization phenomena at low temperatures and strain rates.

Subject Keywords

Mechanical Engineering, General Materials Science, Mechanics of Materials, Condensed Matter Physics

URI

https://hdl.handle.net/11511/57633

Journal

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

DOI

https://doi.org/10.1016/j.msea.2016.02.054

Collections

Department of Metallurgical and Materials Engineering, Article

Suggestions

OpenMETU
Core

Hydrothermal BaTiO3 thin films from nanostructured Ti templates Akyildiz, Hasan; Casper, Michelle D.; Ayguen, Seymen M.; Lam, Peter G.; Maria, Jon P. (Cambridge University Press (CUP), 2011-02-01) Polycrystalline BaTiO3 thin films have been prepared by hydrothermal reaction with sputter-deposited nanostructured reactive Ti templates designed to control net diffusion direction and distance. Templates were prepared in two morphologies, i.e., planar and nanopillar. The samples produced from flat templates showed sluggish transformation kinetics and an eventual termination of reaction without fully consuming the Ti metal. Templates with pillar morphology, on the other hand, could be transformed to phase-...
Contact mechanics problem between an orthotropic graded coating and a rigid punch of an arbitrary profile ARSLAN, ONUR; Dağ, Serkan (Elsevier BV, 2018-01-01) Singular integral equation (SIE) and finite element methods are developed for sliding contact analysis of a finite thickness orthotropic graded coating, which is perfectly bonded to an isotropic substrate. Orthotropic stiffness coefficients of the coating vary exponentially through the coating thickness. The coating is assumed to be loaded by a frictional rigid punch of an arbitrary profile. In the SIE formulation, governing partial differential equations are derived in accordance with the theory of plane e...
Temperature dependence of magnetic and thermal properties of chiral HyFe and HyMn close to phase transitions by using the Landau mean field model Tari, Ozlem; Yurtseven, Hasan Hamit (Elsevier BV, 2019-04-15) Magnetic and thermal properties of chiral metal formate frameworks (MOFs) of NH2NH3M(HCOO)(3), M = Fe, Mn, namely, HyFe and HyMn are investigated close to phase transitions by using Landau phenomenological model. By expanding the free energy in terms of the order parameter, for magnetic properties the temperature dependence of magnetization and inverse magnetic susceptibility, and for thermal properties the heat capacity and entropy are calculated for chiral HyFe and HyMn close to phase transitions using th...
Optical characteristics of Bi12SiO20 single crystals by spectroscopic ellipsometry Isik, M.; Delice, S.; Nasser, H.; Hasanlı, Nızamı; Darvishov, N. H.; Bagiev, V. E. (Elsevier BV, 2020-12-01) Structural and optical characteristics of Bi12SiO20 single crystal grown by the Czochralski method were investigated by virtue of X-ray diffraction (XRD) and spectroscopic ellipsometry measurements. XRD analysis indicated that the studied crystal possesses cubic structure with lattice parameters of a = 1.0107 nm. Spectral dependencies of several optical parameters like complex dielectric constant, refractive index, extinction and absorption coefficients were determined using ellipsometry experiments perform...
Transient and steady state photoelectronic analysis in TlInSe2 crystals QASRAWI, ATEF FAYEZ HASAN; Hasanlı, Nızamı (Elsevier BV, 2011-08-01) The temperature and illumination effects on the transient and steady state photoconductivities of TlInSe2 crystals have been studied. Namely, two recombination centres located at 234 and at 94 meV and one trap center located at 173 meV were determined from the temperature-dependent steady state and transient photoconductivities, respectively. The illumination dependence of photoconductivity indicated the domination of sublinear and supralinear recombination mechanisms above and below 160 K, respectively. Th...

Citation Formats

D. Sagapuram, M. Efe, K. P. Trumble, and S. Chandrasekar, “Flow transitions and flow localization in large-strain deformation of magnesium alloy,” MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, pp. 295–305, 2016, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/57633.