Strain dependence of the volume fraction of hard regions in the composite model of plastic deformation and related substructural quantities

1992 ◽  
Vol 151 (2) ◽  
pp. 161-168 ◽  
Author(s):  
F. Dobeš
Keyword(s):  
Plastic Deformation ◽  
Volume Fraction ◽  
Composite Model ◽  
Strain Dependence

scholarly journals Microstructural Characterization and Mechanical Properties of Ti-6Al-4V Alloy Subjected to Dynamic Plastic Deformation Achieved by Multipass Hammer Forging with Different Forging Temperatures

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Xiurong Fang ◽  
Jiang Wu ◽  
Xue Ou ◽  
Fuqiang Yang
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Volume Fraction ◽  
Microstructural Characterization ◽  
Optical Microscope ◽  
Strain Rates ◽  
Materials Properties ◽  
Forging Process ◽  
Hammer Forging ◽  
Dynamic Plastic Deformation

Dynamic plastic deformation (DPD) achieved by multipass hammer forging is one of the most important metal forming operations to create the excellent materials properties. By using the integrated approaches of optical microscope and scanning electron microscope, the forging temperature effects on the multipass hammer forging process and the forged properties of Ti-6Al-4V alloy were evaluated and the forging samples were controlled with a total height reduction of 50% by multipass strikes from 925°C to 1025°C. The results indicate that the forging temperature has a significant effect on morphology and the volume fraction of primary α phase, and the microstructural homogeneity is enhanced after multipass hammer forging. The alloy slip possibility and strain rates could be improved by multipass strikes, but the marginal efficiency decreases with the increased forging temperature. Besides, a forging process with an initial forging temperature a bit above β transformation and finishing the forging a little below the β transformation is suggested to balance the forging deformation resistance and forged mechanical properties.

Magnetic Characterization of SUS316L Deformed by High Pressure Torsion

2011 ◽  
Vol 239-242 ◽  
pp. 1300-1303
Author(s):  
Hong Cai Wang ◽  
Minoru Umemoto ◽  
Innocent Shuro ◽  
Yoshikazu Todaka ◽  
Ho Hung Kuo
Keyword(s):  
Plastic Deformation ◽  
High Pressure ◽  
Stainless Steel ◽  
Phase Transformation ◽  
Austenitic Stainless Steel ◽  
Volume Fraction ◽  
High Pressure Torsion ◽  
Austenitic Matrix ◽  
Magnetic Characterization

SUS316L austenitic stainless steel was subjected to severe plastic deformation (SPD) by the method of high pressure torsion (HPT). From a fully austenitic matrix (γ), HPT resulted in phase transformation from g®a¢. The largest volume fraction of 70% a¢ was obtained at 0.2 revolutions per minute (rpm) while was limited to 3% at 5rpm. Pre-straining of g by HPT at 5rpm decreases the volume fraction of a¢ obtained by HPT at 0.2rpm. By HPT at 5rpm, a¢®g reverse transformation was observed for a¢ produced by HPT at 0.2rpm.

scholarly journals A Dislocation-Based Theory for the Deformation Hardening Behavior of DP Steels: Impact of Martensite Content and Ferrite Grain Size

2010 ◽  
Vol 2010 ◽  
pp. 1-16 ◽  
Author(s):  
Yngve Bergström ◽  
Ylva Granbom ◽  
Dirk Sterkenburg
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Deformation Process ◽  
Volume Fraction ◽  
High Energy ◽  
Martensite Content ◽  
Plastic Deformation Process ◽  
Deformation Hardening ◽  
Dp Steels ◽  
Ferrite Grain Size

A dislocation model, accurately describing the uniaxial plastic stress-strain behavior of dual phase (DP) steels, is proposed and the impact of martensite content and ferrite grain size in four commercially produced DP steels is analyzed. It is assumed that the plastic deformation process is localized to the ferrite. This is taken into account by introducing a nonhomogeneity parameter, f(ε), that specifies the volume fraction of ferrite taking active part in the plastic deformation process. It is found that the larger the martensite content the smaller the initial volume fraction of active ferrite which yields a higher initial deformation hardening rate. This explains the high energy absorbing capacity of DP steels with high volume fractions of martensite. Further, the effect of ferrite grain size strengthening in DP steels is important. The flow stress grain size sensitivity for DP steels is observed to be 7 times larger than that for single phase ferrite.

Percolation Effects in the Mechanical Properties of Granular Ni-A12O3 thin films

1990 ◽  
Vol 195 ◽  
Author(s):  
T.E. Schlesinger ◽  
A. Gavrin ◽  
R.C. Cammarata ◽  
C.-L. Chien
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Plastic Deformation ◽  
Magnetic Properties ◽  
Percolation Threshold ◽  
Volume Fraction ◽  
Electrical And Magnetic Properties ◽  
Low Load

ABSTRACTThe mechanical properties of sputtered Ni-Al2O3 granular thin films were investigated by low load microharaness testing. It was found that the microhardness of these films displayed a percolation threshold at a nickel volume fraction of about 0.6, below which the hardness is greatly enhanced. This behavior is qualitatively similar to the electrical and magnetic properties of these types of films. A percolation threshold in hardness can be understood as due to a change in the mechanism for plastic deformation.

Forming Limit Analysis of Hexagonal Metal Considering Volume Fraction of Deformation Twinning

2019 ◽  
Vol 794 ◽  
pp. 226-231
Author(s):  
Tomoaki Koga ◽  
Yuichi Tadano
Keyword(s):  
Plastic Deformation ◽  
Finite Element ◽  
Crystal Plasticity ◽  
Limit Analysis ◽  
Volume Fraction ◽  
Deformation Twinning ◽  
Forming Limit ◽  
Strain Paths ◽  
Homogenization Scheme ◽  
Slip Deformation

In the plastic deformation of hexagonal metals, deformation twinning plays an important role as well as slip deformation. Therefore, a modelling of deformation twinning is essential in the crystal plasticity modeling. In this study, a model considering the volume fraction of deformation twinning is presented in the framework of crystal plasticity, and it is combined with a finite element-based homogenization scheme to represent the polycrystalline behavior. The presented model is adopted to a sheet necking formulation. Plastic flow behaviors under several strain paths are evaluated using the present framework, and the effect of volume fraction of deformation twinning on the formability of hexagonal metal is discussed.

Effect of Zr on Structure and Resistance to Intergranular Corrosion of Severely Deformed 2024 Aluminum Alloy

2019 ◽  
Vol 31 ◽  
pp. 35-42
Author(s):  
Stanislav Krymskiy ◽  
Rafis Ilyasov ◽  
Elena Avtokratova ◽  
Oleg Sitdikov ◽  
Anastasia Khazgalieva ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Aluminum Alloy ◽  
Severe Plastic Deformation ◽  
Intergranular Corrosion ◽  
Artificial Aging ◽  
Volume Fraction ◽  
S Phase ◽  
2024 Aluminum Alloy ◽  
Excess Phases ◽  
Electrochemical Potentials

Effects of severe plastic deformation by isothermal сryorolling with a strain of e~2 and subsequent natural and artificial aging on the structure and resistance to intergranular corrosion (IGC) of the preliminary quenched 2024 aluminum alloy of standard and Zr modified compositions were investigated. Increasing the temperature of aging leads to decreasing the alloy IGC resistance due to precipitation of more stable strengthening S-phase (Al2CuMg), rising difference of electrochemical potentials at grain and subgrain boundaries. Zr additions, оn the opposite, significantly increased the alloy IGC resistance in both naturally and artificially aged conditions, reducing its depth and intensity. The main structural factor, influencing the alloy corrosion behavior, is excess phases: their composition, volume fraction and distribution.

A Constitutive Model for Shape Memory Alloys Involving Transformation, Reorientation and Plasticity

2013 ◽  
Vol 535-536 ◽  
pp. 105-108
Author(s):  
Xiang He Peng ◽  
Min Mei Chen ◽  
Jun Wang
Keyword(s):  
Plastic Deformation ◽  
Constitutive Model ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Volume Fraction ◽  
Transformation Rule ◽  
Constitutive Behavior ◽  
Plastic Parts

A constitutive model is developed for shape memory alloys (SMAs) based on the concept that an SMA is a mixture composed of austenite and martensite. The deformation of the martensite is separated into elastic, thermal, reorientation and plastic parts, and that of the austenite is separated into elastic, thermal and plastic parts. The volume fraction of each phase is determined with the modified Tanaka’s transformation rule. The typical constitutive behavior of some SMAs, including pseudoelasticity, shape memory effect, plastic deformation as well as its effects, is analyzed.

Transformation/Deformation Behavior and its Constitutive Equation for Ti-Ni-Cu Shape Memory Alloy

2008 ◽  
Vol 59 ◽  
pp. 129-134
Author(s):  
Yuji Takeda ◽  
Takaei Yamamoto ◽  
M. Uegaki ◽  
Hiroki Cho ◽  
Toshio Sakuma ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Constitutive Equation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Constitutive Equations ◽  
Deformation Behavior ◽  
Volume Fraction ◽  
Transformation Process ◽  
Reverse Transformation ◽  
Transformation Behavior

This paper describes the transformation and deformation behavior and its constitutive equation for Ti-41.7Ni-8.5Cu (at%) shape memory alloy. Plastic deformation after pre-deformation is investigated using the volume fraction of slip-deformed martensite. New kinetics and constitutive equations are proposed for the reverse transformation process. The material constants in the proposed equationa are determined from the results of tensile and heating/cooling tests of Ti-41.7Ni-8.5Cu (at%) shape memory alloy. The calculated results describe well the deformation and transformation behavior affected by pre-strain.

Effect of Minor Addition Ta on the Thermal Stability and Corrosion Resistance of Ti-Zr-Cu-Pd Bulk Metallic Glasses

2013 ◽  
Vol 750 ◽  
pp. 23-26 ◽  
Author(s):  
Feng Xiang Qin ◽  
Guo Qiang Xie ◽  
Sheng Li Zhu ◽  
Zhen Hua Dan
Keyword(s):  
Thermal Stability ◽  
Plastic Deformation ◽  
Corrosion Resistance ◽  
Metallic Glasses ◽  
Anodic Polarization ◽  
Volume Fraction ◽  
Bulk Metallic Glasses ◽  
Large Plastic Deformation ◽  
Minor Addition ◽  
Proper Volume

In this research, the effect of Ta addition on the formation, thermal stability and corrosion behavior of Ti-Zr-Cu-Pd bulk metallic glasses were investigated. The results revealed with minor addition of Ta, higher corrosion resistance and compressive strength as well as large plastic deformation were achieved. Minor addition Ta is effective for the formation of more protectively passive film during the process of anodic polarization. In addition, proper volume fraction nanoparticle with small size is responsible for the large plastic deformation of the as-cast Ti-based bulk metallic glasses with 1% Ta addition.

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