scholarly journals Johnson–Cook Parameter Identification for Commercially Pure Titanium at Room Temperature under Quasi-Static Strain Rates

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3887
Author(s):  
Alice Siegel ◽  
Sébastien Laporte ◽  
Fabien Sauter-Starace
Keyword(s):  
Strain Rate ◽  
Room Temperature ◽  
Pure Titanium ◽  
Element Model ◽  
Tensile Tests ◽  
Strain Rates ◽  
Commercially Pure Titanium ◽  
Elastoplastic Behavior ◽  
Plastic Parts ◽  
Cook Model

Background: To simulate mechanical shocks on an intracranial implant called WIMAGINE®, Clinatec chose a Johnson–Cook model to account for the viscoplastic behavior of grade 2 titanium in a dynamic study using Radioss©. Methods: Thirty tensile specimens were subjected to tensile tests at room temperature, and the influence of the strain rate (8 × 10−3 and 8 × 10−2 s−1) and sandblasting was analyzed. Relaxations were included in the tests to analyze viscosity phenomena. Results: A whole set of parameters was identified for the elastic and plastic parts. Strain rate influence on stress was negligible at these strain rates. As expected, the sandblasting hardened the material during the tests by decreasing the hardening parameters, while local necking occurred at an earlier strain. Conclusions: This article provides the parameters of a Johnson–Cook model to simulate the elastoplastic behavior of pure titanium (T40, grade 2) in Finite Element Model (FEM) software.

Improvement in Ductility in Commercially Pure Titanium Alloys by Stress Relaxation at Room Temperature

2014 ◽  
Vol 611-612 ◽  
pp. 92-98 ◽  
Author(s):  
Irena Eipert ◽  
Giribaskar Sivaswamy ◽  
Rahul Bhattacharya ◽  
Muhammad Amir ◽  
Paul Blackwell
Keyword(s):  
Stress Relaxation ◽  
Titanium Alloys ◽  
Yield Point ◽  
Room Temperature ◽  
Pure Titanium ◽  
Tensile Tests ◽  
Tensile Behaviour ◽  
Strain Rates ◽  
Commercially Pure Titanium ◽  
Commercially Pure

Present work focusses on the effect of stress relaxation on the tensile behaviour of two commercially pure titanium alloys of different strength levels (Grade 1 and Grade 4) subjected to tensile tests at room temperature. The stress relaxation tests were performed by interrupting the tensile tests at regular strain intervals of 5% in the plastic region of the tensile curve and compared to the monotonic tensile tests at different strain rates ranging from 10-4to 10-1s-1. To understand the effect of anisotropy, samples were taken along 0° and 90° to rolling direction (RD) for both the alloys. Improvement in ductility of different levels at all the strain rates was observed in both the alloys when stress relaxation steps were introduced as compared to monotonic tests. However there is not much change in the flow stress as well as in strain hardening behaviour of the alloys. The true stress-true strain curves of Grade 4 samples taken in 90° to RD exhibited discontinuous yielding phenomenon after the yield point, which is termed as a yield-point elongation (YPE). The improvement in ductility of the Cp-Ti alloys can be linked to recovery process occurring during the stress relaxation steps which resulted in the improvement in ductility after repeated interrupted tensile tests. The paper presents and summarise the results based on the stress relaxation for the two different alloys.

scholarly journals Influence of strain rate and heat treatments on tensile and creep properties of Zn-0.15Cu-0.07Ti alloys

DYNA ◽  
2016 ◽  
Vol 83 (195) ◽  
pp. 77-83 ◽  
Author(s):  
María José Quintana Hernández ◽  
José Ovidio García ◽  
Roberto González Ojeda ◽  
José Ignacio Verdeja
Keyword(s):  
Strain Rate ◽  
Room Temperature ◽  
Rolling Direction ◽  
Tensile Tests ◽  
Strain Rates ◽  
Creep Tests ◽  
Design Problems ◽  
Creep Properties ◽  
Heat Treated ◽  
Zn Alloys

The use of Cu and Ti in Zn alloys improves mechanical properties as solid solution and dispersoid particles (grain refiners) may harden the material and reduce creep deformation. This is one of the main design problems for parts made with Zn alloys, even at room temperature. In this work the mechanical behavior of a Zn-Cu-Ti low alloy is presented using tensile tests at different strain rates, as well as creep tests at different loads to obtain the value of the strain rate coefficient m in samples parallel and perpendicular to the rolling direction of the Zn strip. The microstructure of the alloy in its raw state, as well as heat treated at 250°C, is also analyzed, as the banded structure produced by rolling influences the strengthening mechanisms that can be achieved through the treatment parameters.

Monotonic and cyclic behavior of the nitrogen ion-implanted commercially pure-titanium

2021 ◽  
Vol 15 (1) ◽  
pp. 7662-7670
Author(s):  
N. Ali ◽  
M.S. Mustapa ◽  
T. Sujitno ◽  
T.E. Putra ◽  
Husaini .
Keyword(s):  
Material Properties ◽  
Room Temperature ◽  
Pure Titanium ◽  
Tensile Tests ◽  
Fatigue Tests ◽  
Cyclic Behavior ◽  
Strain Hardening Exponent ◽  
Commercially Pure Titanium ◽  
Commercially Pure ◽  
Nitrogen Ion

This research aims to study the behavior of monotonic and cyclic plastic deformation on commercially pure titanium which has undergone surface treatment using the nitrogen ion implantation method. The doses of 2.0×1017 ions/cm2 and the energy of 100 keV were used to implant the nitrogen ions into the CpTi. Monotonic properties tests were performed in a laboratory air and at room temperature using ASTM E8 standard specimens. Fatigue and corrosion fatigue tests were conducted in a laboratory  air and in artificial saline solutions, at room temperature using ASTM 1801-97 specimens. Tensile tests were carried out with constant displacement rate and fatigue tests were carried under fully-reversed with stress-controlled conditions with stress amplitudes 230, 240, 250, 260, 270 and 280 MPa. The results showed the material properties of monotonic behavior for CpTi and Nii-Ti; tensile strength (σu) of 497 and 539 MPa and for 0.2% offset yield strength (σy) of 385 and 440 MPa, respectively and of cyclic behavior; cyclic strength coefficient (k’) of 568.41 and 818.64 and cyclic strain hardening exponent (n’) of 0.176 and 0.215, respectively. This study has succeeded in producing useful new material properties that will contribute to the field of material science and engineering.

Serrated Flow in an 11Cr Ferritic/Martensitic Steel

2014 ◽  
Vol 894 ◽  
pp. 125-128 ◽  
Author(s):  
Zhi Qiang Xu ◽  
Yin Zhong Shen ◽  
Bo Ji ◽  
Sheng Zhi Li ◽  
Ai Dang Shan
Keyword(s):  
Tensile Stress ◽  
Strain Rate ◽  
Yield Stress ◽  
Room Temperature ◽  
Martensitic Steel ◽  
Flow Behavior ◽  
Tensile Tests ◽  
Ultimate Tensile Stress ◽  
Strain Rates ◽  
Serrated Flow

Serrated flow behavior of an 11Cr ferritic/martensitic steel was investigated through tensile tests at initial strain rates of 2×10-510-3 s-1 at temperatures ranging from room temperature to 973 K. Serrated flow occurred at three temperature regions of room temperature, 573 K and 773973 K when tensile tests were conducted at a strain rate of 2×10-4 s-1. Serrations are also observed in the steel during tension at temperatures of 573 K and 773973 K at a strain rate of 2×10-5 s-1. With increasing tensile temperature, the yield stress and ultimate tensile stress of the steel were gradually decreased and quickly dropped at temperatures higher than 773 K, while the elongation of the steel was decreased to a minimum at 600 K, and then dramatically increased at temperatures higher than 600 K.

scholarly journals Biaxial Tensile Behavior of Commercially Pure Titanium under Various In-Plane Load Ratios and Strain Rates

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 155
Author(s):  
Wei Zhang ◽  
Zhikang Zhu ◽  
Changyu Zhou ◽  
Xiaohua He
Keyword(s):  
Tensile Strength ◽  
Strain Rate ◽  
Tensile Deformation ◽  
Pure Titanium ◽  
Load Ratio ◽  
Tensile Behavior ◽  
Strain Rates ◽  
Commercially Pure Titanium ◽  
Commercially Pure ◽  
Biaxial Tensile

The aim of the present work is to contribute to the characterization of the biaxial tensile behavior of commercially pure titanium, under various in-plane loading conditions at room temperature, by a non-contact digital image correlation system. Several loading conditions, with load ratio ranging from 4:0 to 0:4 and displacement rate ranging from 0.001 to 0.1 mm/s, are examined. It is found that the yield strength and ultimate tensile strength of biaxial sample are greater than that of uniaxial sample, where the equi-biaxial sample shows the highest strength. It is also observed that increase in strain rate leads to remarkable improvement of tensile strength. Fractographic analysis indicates that the shape and size of dimples are load ratio and strain rate dependent. Additionally, a modified Johnson–Cook constitutive model was proposed to account for the effect of strain rate on biaxial tensile deformation. The experimental results are in good agreement with the simulated results, indicating that the proposed model is reliable to predict biaxial tensile deformation of commercially pure titanium at different strain rates.

Serrated Flow in 316LN Austenitic Stainless Steel

2013 ◽  
Vol 455 ◽  
pp. 159-162 ◽  
Author(s):  
Zhi Qiang Xu ◽  
Yin Zhong Shen
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Strain Rate ◽  
Room Temperature ◽  
Flow Behavior ◽  
Tensile Tests ◽  
Dynamic Strain ◽  
Strain Rates ◽  
Serrated Flow ◽  
Substitutional Solute

Serrated flow behavior of the 316LN austenitic stainless steel was investigated through tensile tests at initial strain rates of 2×10-5 to 10-4 s-1 at temperatures ranging from room temperature to 1048 K. Serrated flow occurred at room temperature and 6981048K at the strain rate of 2×10-4 s-1, as well as at temperatures of 623673 K at the strain rate of 2×10-5 s-1. Type A, A+B, C and E serrations appeared. The activation energy for the occurrence of serrated flow at high temperatures was about 327 kJ/mol. The dynamic strain aging caused by the interaction between substitutional solute Cr atoms and moving dislocations is considered as the mechanism of serrated flow at the temperatures higher than 973 K.

Tensile Property of Electrochemically Polished Titanium Alloy

2014 ◽  
Vol 939 ◽  
pp. 146-151
Author(s):  
Takashi Ikushima ◽  
Tetsuhide Shimizu ◽  
Ming Yang
Keyword(s):  
Titanium Alloy ◽  
Tensile Test ◽  
Strain Rate ◽  
Room Temperature ◽  
Quantitative Measurement ◽  
Rate Sensitivity ◽  
Tensile Tests ◽  
Strain Rates ◽  
Electrochemical Polishing ◽  
Different Thickness

Tensile tests of titanium alloy (Ti-6Al-4V) with different thickness of 0.4 mm and 0.3 mm, were performed to investigate thickness dependency of superplasticity. To keep the same inner microstructure between specimens with different thicknesses, electrochemical polishing method was applied to reduce thickness. By keeping the voltage for the electrochemical polishing as 30 V the thickness decreased as linear with respect to polishing time. Further, tensile tests of 0.4 mm with strain rate 9.310-4 sec-1 were conducted at room temperature and 850 °C. And the superplasticity of 450 % elongation was obtained at 850 °C. For quantitative measurement of superplasticity, strain rate sensitivity (m value) was calculated from the tensile test by changing strain rate. The m values of the unpolished 0.4 mm specimen and the polished 0.3 mm specimen were 0.52 and 0.43, respectively. Strain rates to calculate the m value were 510-4 sec-1 and 110-3 sec-1. Consequently the reduction of thickness resulted in the reduction of m value, which means less superplasticity for thinner sheets of Ti-6Al-4V.

scholarly journals Ultra-High Strain Rate Constitutive Modeling of Pure Titanium Using Particle Impact Test

2020 ◽  
Vol 87 (9) ◽  
Author(s):  
Xuchen Wang ◽  
Mostafa Hassani
Keyword(s):  
Strain Rate ◽  
Constitutive Modeling ◽  
Impact Test ◽  
High Strain ◽  
Pure Titanium ◽  
Particle Impact ◽  
Strain Rates ◽  
Commercially Pure Titanium ◽  
High Strain Rates ◽  
High Deformation

Abstract With the advent of advanced testing techniques such as laser-induced particle impact test, it is possible to study materials mechanics under extremely high deformation rates, i.e., above 106 s−1, a relatively less explored regime of strain rates. Inspired by the classical Taylor impact test, in this study, we accelerate microparticles of commercially pure titanium to a range of impact velocities, from 144 to 428 m/s, toward a rigid substrate and record their deformation upon impact in real-time. We also conduct finite element modeling of the experimentally recorded impacts using two constitutive equations, namely, Johnson–Cook and Zerilli–Armstrong. We show that the titanium microparticles experience strain rates in the range of 106–1010 s−1 upon impact. We evaluate the capability of the Johnson–Cook and Zerilli–Armstrong equations in predicting the deformation response of pure Ti at ultra-high strain rates. With an optimization-based constitutive modeling approach, we also propose updated strain rate-related parameters for both equations and improve the extent to which the two models can describe the deformation of pure titanium at ultra-high strain rates.

scholarly journals LOCALIZATION OF PLASTIC DEFORMATION IN COMMERCIALLY PURE TITANIUM IN A COMPLEX STRESS STATE UNDER HIGH-SPEED TENSION

2021 ◽  
pp. 89-102
Author(s):  
V.V. Skripnyak ◽  
◽  
K.V. Iokhim ◽  
V.A. Skripnyak ◽  
◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Stress State ◽  
Strain Rate ◽  
High Speed ◽  
Pure Titanium ◽  
Complex Stress ◽  
Complex Stress State ◽  
Strain Rates ◽  
Commercially Pure Titanium ◽  
Commercially Pure

In this work, the effect of a triaxiality stress state on the mechanical behavior and fracture of commercially pure titanium VT1-0 (Grade 2) in the range of strain rates from 0.1 to 1000 s−1 is studied. Tensile tests are carried out using a servo-hydraulic testing machine Instron VHS 40 / 50-20 on flat specimens with a constant cross-sectional area and on flat specimens with a notch. To study the effect of the complex stress state on the ultimate deformation before fracture, the samples with the notch of various radii (10, 5, 2.5 mm) are used in the experiments. Phantom V711 is employed for high-speed video registration of specimen’s deformation. Deformation fields in a working part of the sample are investigated by the digital image correlation method. It is shown that the effect of the strain rate on the ultimate deformations before fracture has a nonmonotonic behavior. An analysis of strain fields in the working part of the samples shows that the degree of uniform deformation of the working part decreases with an increase in the strain rate. At strain rates above 1000 s−1, the shear bands occur at the onset of a plastic flow. Commercially pure titanium undergoes fracture due to the nucleation, growth, and coalescence of damages in the bands of localized plastic deformation oriented along the maximum shear stresses. The results confirm that the fracture of commercially pure titanium exhibits ductile behavior at strain rates varying from 0.1 to 1000 s−1, at a triaxiality stress parameter in the range of 0.333 ≤ η <0.467, and at a temperature close to 295 K.

Deformation Behaviour of Titanium in Torsion

2011 ◽  
Vol 702-703 ◽  
pp. 826-829 ◽  
Author(s):  
Nilesh P. Gurao ◽  
Satyam Suwas
Keyword(s):  
Strain Rate ◽  
Deformation Behaviour ◽  
Pure Titanium ◽  
Shear Plane ◽  
Deformation Texture ◽  
Shear Direction ◽  
Strain Rates ◽  
Commercially Pure Titanium ◽  
Plane Direction ◽  
Evolution Of Microstructure

The evolution of microstructure and texture in Hexagonal Close Pack commercially pure titanium has been studied in torsion in a strain rate regime of 0.001 to 1 s-1. Free end torsion tests carried out on titanium rods indicated higher stress levels at higher strain rate but negligible change in the strain-hardening behaviour. There was a decrease in the intra-granular misorientation while a negligible change in the amount of contraction and extension twins was observed with increase in strain rate. The deformed samples showed a C1 fibre (c-axis is first rotated 90° in shear direction and then +30° in shear plane direction) at all the strain rates. With the increase in strain rate, there was an increase in the intensity of the C1 fibre and it became more heterogeneous with a strong {11 6} component. In the absence of extensive twinning, pyramidal slip system is attributed for the observed deformation texture. The present investigation, therefore, substantiates the theoretical prediction of increase in strength of texture with strain rate in torsion.

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