Paper Search Console

Home Search Page About Contact

Journal Title

Title of Journal: Metall and Mat Trans A

Search In Journal Title:

Abbravation: Metallurgical and Materials Transactions A

Search In Journal Abbravation:

Publisher

Springer US

Search In Publisher:

ISSN

1543-1940

Search In ISSN:
Search In Title Of Papers:

Influence of Temperature and Grain Size on Thresho

Authors: H Watanabe T Mukai K Higashi
Publish Date: 2008/07/11
Volume: 39, Issue: 10, Pages: 2351-
PDF Link

Abstract

The parametric dependencies of threshold stress for superplastic flow were characterized over a wide range of temperatures using a finegrained magnesium alloy with various grain sizes The threshold stress was proportional to the reciprocal of the square root of the grain size at 473 K whereas it was independent of the grain size at 598 K The threshold stress decreased with increasing deformation temperature more quickly than the shear modulus did It was suggested that the temperature dependence of the threshold stress is associated with the interaction between the solute atoms and dislocations The origin of the threshold stress probably resulted from the dislocations breaking away from the solute atmospheres formed in the grain boundaries and in the lattice at low temperatures and at high temperatures respectivelyGrain growth during superplastic flow caused both by the exposure at high temperatures and by welldocumented straininduced grain growth has a visible effect on the stressstrain curves because the flow stress during superplastic flow increases with increasing grain size work hardening occurs as a result of grain growth In fact due to the ease of grain growth in several magnesium alloys a graingrowth effect on the flow stress is suggested to be the origin of threshold stresslike behavior in the lowstrainrate range66 The authors however assumed that the grain sizes after static annealing before straining remain unchanged during the tensile deformation up to ε = 01 for this reason the effect of grain growth during deformation to ε = 01 on the calculated thresholdstress values was neglected throughout that articleIn the present study the linearextrapolation method was adopted to calculate the thresholdstress values Inspection of Figures 5 and 7 revealed that the n = 2 provided a linear extrapolation even in the lowstrainrate range If the threshold stress varies with exposure time or strain rate the data will not provide a linear extrapolation The linearity over a wide range of strain rates observed in the present study indicates the absence of significant grain growth even in the lowstrainrate rangeIn order to experimentally confirm the grainsize stability of the materials used in the present study both the strainhardening behavior and graingrowth behavior in the gage portion were examined under several extreme conditions the slowest strain rates or the highest temperatures The arrows in Figures 2 and 4a show the deformation conditions examined in Appendix A The microstructures of the gage portion were observed after plastic deformation to ε ≈ 01 at which the flow stress was determinedTrue stresstrue strain curves up to ε = 02 for a the asextruded alloy deformed at 523 K and 1 × 10−5 s−1 b the asextruded alloy deformed at 623 K and 1 × 10−3 s−1 and c the annealed alloy deformed at 473 K and 3 × 10−6 s−1 True stresstrue strain curve for the asextruded AZ31 alloy deformed at 623 K and 1 × 10−3 s−167 is also shown in bThe average grain sizes d and distribution of grain size in the PM ZK61 before deformation upper rows and after deformation to ε ≈ 01 lower rows a and b for the asextruded alloy deformed at 523 K and 1 × 10−5 s−1 c and d for the asextruded alloy deformed at 623 K and 1 × 10−3 s−1 and e and f for the annealed alloy deformed at 473 K and 3 × 10−6 s−1It is beneficial to examine the elastic modulus of the present alloy at elevated temperatures The material used for measurement was ZK60 Mg6 mass pct Zn05 mass pct Zr alloy assuming similar elastic properties between ZK61 and ZK60 This will be confirmed from the fact that the slight difference in chemical composition does not generally affect the elastic moduli Hotextruded ZK60 which was annealed at 723 K for 5 hours before the measurement was machined into a rectangular specimen The specimen had a length of 60 mm a width of 10 mm and a thickness of 15 mm The annealing treatment led to some sort of bimodal grain mixture with fine grains 15 μm in size and coarse grains 100 to 500 μm in size The dynamic shear modulus G was measured up to 493 K in every 10 K by employing the method of resonant vibration in cantilever specimen holdingThe measured dynamic shear modulus of ZK60 decreased linearly with increasing temperature up to ∼450 K This is in contrast to the behavior of AZ91 Mg9 mass pct Al1 mass pct Zn alloy with a grain size of 70 to 300 μm68 the temperature dependence of the measured modulus did not deviate from linearity dG/dT = −00082 GPa K−1 at least up to 623 K The deviation in ZK60 may be ascribable to the relaxation from the occurrence of GBS65 which results from the existence of fine grains 15 μm in size The dynamic unrelaxed shear modulus of ZK60 which was derived by fitting the data from RT to 450 K was calculated to be G = 1833 − 00090 T where the units of G and T are GPa and K respectively The shear modulus from 473 to 623 K used for the present analysis was estimated by extrapolation


Keywords:

References


.
Search In Abstract Of Papers:
Other Papers In This Journal:

  1. In Situ Neutron-Diffraction Studies on the Creep Behavior of a Ferritic Superalloy
  2. Influence of Sintering under Nitrogen Atmosphere on Microstructures of Powder Metallurgy Duplex Stainless Steels
  3. Temperature Dependence of Diffuse Scattering in PZN
  4. Synthesis and Characterization of Novel Chromium-Free Nickel Alloy Electrode Materials
  5. Synthesis and Characterization of Novel Chromium-Free Nickel Alloy Electrode Materials
  6. Dynamic Stress–Strain Behavior in ZrTiCuNiAl Noncrystalline Alloys Pretreated Under High Pressures
  7. XPS Analysis of Ti6Al4V Oxidation Under UHV Conditions
  8. Effect of Sr Additions on the Microstructure and Strength of a Mg-Al-Ca Ternary Alloy
  9. Foreword
  10. Failure during Sheared Edge Stretching of Dual-Phase Steels
  11. Computer-Aided Development and Simulation Tools for Shape-Memory Actuators
  12. Computer-Aided Development and Simulation Tools for Shape-Memory Actuators
  13. Effect of Application of Short and Long Holds on Fatigue Life of Modified 9Cr-1Mo Steel Weld Joint
  14. Effects of Alloying Elements on Microstructure and Properties of Magnesium Alloys for Tripling Ball
  15. Microstructural Control of Ti-Al-Nb-W-B Alloys
  16. Three-Dimensional Thermomechanical Simulation and Experimental Validation on Failure of Dissimilar Material Welds
  17. The Role of Σ9 Boundaries in Grain Boundary Engineering
  18. Controlling Plastic Flow across Grain Boundaries in a Continuum Model
  19. Microstructural Evolution during Creep of Alloy 800HT in the Temperature Range 600 °C to 1000 °C
  20. Mechanical Properties of the TiAl IRIS Alloy
  21. Precipitation Modeling in Nitriding in Fe-M Binary System
  22. Glass-Forming Ability for Mg-Cu-Nd Alloys
  23. Kinetics of the γ →  ε Martensitic Transformation in Fine-Grained Fe-26Mn-0.14C Austenitic Steel
  24. Nanoscale Copper and Copper Compounds for Advanced Device Applications
  25. A Geometric Framework for Mesoscale Models of Recrystallization
  26. Microstructure Evolution and Rapid Solidification Behavior of Blended Nickel-Based Superalloy Powders Fabricated by Laser Powder Deposition
  27. Laser Quenching of Ionic Nitrided Steel: Effect of Process Parameters on Microstructure and Optimization
  28. Effect of Alloying Additions on Phase Equilibria and Creep Resistance of Alumina-Forming Austenitic Stainless Steels
  29. Deformation Mechanisms in the Near- β Titanium Alloy Ti-55531
  30. Shape Memory Behavior of Porous NiTi Alloy
  31. Effect of Laves Phase on High-Temperature Deformation and Microstructure Evolution in an 18Cr-2Mo-0.5Nb Ferritic Stainless Steel
  32. Effect of Graphene Nanoplatelets on Wetting, Microstructure, and Tensile Characteristics of Sn-3.0Ag-0.5Cu (SAC) Alloy
  33. Alternate Anodes for the Electrolytic Reduction of UO 2
  34. Measurement and Discussion of Low-Temperature Hot Corrosion Damage Accumulation upon Nickel-Based Superalloy Rene 104
  35. Alternate Anodes for the Electrolytic Reduction of UO 2
  36. Orientation Dependence of the Deformation Microstructure in a Fe-30Ni-Nb Model Austenitic Steel Subjected to Hot Uniaxial Compression
  37. Microstructural Analysis and the Multicolor UV/Violet/Blue/Green/Yellow PL Observed from the Synthesized ZnO Nano-leaves and Nano-rods
  38. Effect of Atmospheric Pressure Plasma Modification on Polyimide and Adhesive Joining with Titanium
  39. Carbide Precipitation During Tempering of a Tool Steel Subjected to Deep Cryogenic Treatment
  40. Multipass Friction-Stir Processing and its Effect on Mechanical Properties of Aluminum Alloy 5086
  41. Reminiscences About a Chemistry Nobel Prize Won with Metallurgy: Comments on D. Shechtman and I. A. Blech; Metall. Trans. A , 1985, vol. 16A, pp. 1005–12
  42. Solute Diffusion Characteristics of a Rapid Hardening Al-Cu-Mg Alloy during the Early Stages of Age Hardening
  43. Induction Tempering vs Conventional Tempering of a Heat-Treatable Steel
  44. Effect of Nb Microalloying and Hot Rolling on Microstructure and Properties of Ultrathin Cast Strip Steels Produced by the CASTRIP ® Process
  45. Study of $$ \{ 11\bar{2} 1\} $$ Twinning in α-Ti by EBSD and Laue Microdiffraction
  46. A Re-examination of the Portevin-Le Chatelier Effect in Alloy 718 in Connection with Oxidation-Assisted Intergranular Cracking
  47. Effects of Carbides on the Microstructural Evolution in Sub-micron Grain 9310 Steel During Isothermal Heat Treatment
  48. Role of Slip Mode on Stress Corrosion Cracking Behavior
  49. Analysis of Slip Activity and Deformation Modes in Tension and Tension-Creep Tests of Cast Mg-10Gd-3Y-0.5Zr (Wt Pct) at Elevated Temperatures Using In Situ SEM Experiments
  50. Multistage Devitrification Behavior of Mg 65 Cu 25 Tb 10 Bulk Metallic Glass
  51. On the Selection of the Optimal Intercritical Annealing Temperature for Medium Mn TRIP Steel
  52. A Numerical Model Describing Multiphase Binary Diffusion in Liquid Metal/Solid Metal Couples
  53. Mechanism of Oxidation of Austenitic Stainless Steels under Conditions of Hot Rolling in Steckel Mills
  54. Evolution of Slip Morphology and Fatigue Crack Initiation in Surface Grains of Ni200
  55. The Effect of the Rate of Cooling from High-Temperature Single-Phase Region on the Microstructure and Magnetic Properties of AlNi Alloys
  56. Friction Stir Welding of Stainless Steel to Al Alloy: Effect of Thermal Condition on Weld Nugget Microstructure
  57. High-Temperature Creep Degradation of the AM1/NiAlPt/EBPVD YSZ System
  58. Perspectives on Permanent Magnetic Materials for Energy Conversion and Power Generation
  59. A New Constitutive Strain-Dependent Garofalo Equation to Describe the High-Temperature Processing of Materials—Application to the AZ31 Magnesium Alloy
  60. Characterization of Fatigue Fracture in Ni-20 Pct Cr Alloys Using White Light Interference Microscopy and Scanning Probe Microscopy
  61. Formation of Fine Clusters in High-Temperature Oxidation of Molten Aluminum
  62. Relationship Between Microstructure, Strength, and Fracture in an Al-Zn-Mg Electron Beam Weld: Part I: Microstructure Characterization
  63. Four-Parameter Hybrid–Bishop–Hill Model Applied to OFE Copper for the Evaluation of Elastic/Yield Limit
  64. Preparation of Freestanding Zn Nanocrystallites by Combined Milling at Cryogenic and Room Temperatures
  65. Effect of Treatment Area on Residual Stress and Fatigue in Laser Peened Aluminum Sheets
  66. Effect of aging on fatigue crack growth at sn-pb/cu interfaces
  67. Scaling of Dislocation Strengthening by Multiple Obstacle Types
  68. Phase Equilibria of Sn-Sb-Ag Ternary System (II): Calculation
  69. An Assessment and Estimation of the Damage Progression Behavior of IN738LC under Various Applied Stress Conditions Based on EBSD Analysis
  70. Bio-corrosion and Cytotoxicity Studies on Novel Zr 55 Co 30 Ti 15 and Cu 60 Zr 20 Ti 20 Metallic Glasses
  71. Thermal Explosion Reaction in the Ti-C System under Air Atmosphere
  72. Scheil–Gulliver Constituent Diagrams
  73. Nanoscale Deformation Behavior of Phase-Reversion Induced Austenitic Stainless Steels: The Interplay Between Grain Size from Nano-Grain Regime to Coarse-Grain Regime
  74. Deformation and Fracture Behavior of Rapidly Solidified and Annealed Iron-Silicon Alloys
  75. Application of Quenching and Partitioning Processing to Medium Mn Steel
  76. DICTRA Simulation of Holding Time Dependence of NbC Size and Experimental Study of Effect of NbC on Austenite Grain Growth
  77. Dynamic Torsional Deformation Behavior of Ultra-Fine-Grained Dual-Phase Steel Fabricated by Equal Channel Angular Pressing
  78. Effects of Strain Rate of Prior Deformation on Corrosion and Corrosive Wear of AISI 1045 Steel in a 3.5 Pct NaCl Solution
  79. Stress and Strain Partitioning of Ferrite and Martensite during Deformation
  80. The Effect of Dilution on Microsegregation in AWS ER NiCrMo-14 Alloy Welding Claddings
  81. Tearing Resistance Properties of Cr-Mo Steels with Internal Hydrogen Determined by the Potential Drop Method
  82. Structures and Electrochemical Hydrogen Storage Properties of the As-Spun RE-Mg-Ni-Co-Al-Based AB 2 -Type Alloys Applied to Ni-MH Battery
  83. Finite Element Analysis of Deformation Due to Ball Indentation and Evaluation of Tensile Properties of Tempered P92 Steel
  84. Influence of Processing Severity During Equal-Channel Angular Pressing on the Microstructure of an Al-Zn-Mg-Cu Alloy
  85. Examination of Spheroidal Graphite Growth and Austenite Solidification in Ductile Iron
  86. Characterization of Plastic Flow Pertinent to the Evolution of Bulk Residual Stress in Powder-Metallurgy, Nickel-Base Superalloys
  87. Experimental and Numerical Study on the Deformation Mechanism in AZ31B Mg Alloy Sheets Under Pulsed Electric-Assisted Tensile and Compressive Tests
  88. Rapid Solidification of Sm-Co Permanent Magnets
  89. The Future of Spatially-Resolved Polychromatic Neutron and X-Ray Microdiffraction
  90. Regression Analysis of Thermal Conductivity Based on Measurements of Compacted Graphite Irons
  91. Hardness Evolution of Gamma-Irradiated Polyoxymethylene
  92. The Origin of Microstructural Diversity, Texture, and Mechanical Properties in Electron Beam Melted Ti-6Al-4V
  93. On the Relation of Microstructure and Texture Evolution in an Austenitic Fe-28Mn-0.28C TWIP Steel During Cold Rolling
  94. On the Onset of a Steady State in Body-Centered Cubic Iron during Severe Plastic Deformation at Low Homologous Temperatures
  95. Processing and Characterization of Functionally Graded Aluminum (A319)—SiC p Metallic Composites by Centrifugal Casting Technique
  96. Dynamic Simulation of the Thermal Decomposition of Pyrite Under Vacuum
  97. Correlation of Fractographic Features with Mechanical Properties in Systematically Varied Microstructures of Cu-Strengthened High-Strength Low-Alloy Steel

Search Result: