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.

The Influence of Strain Rate on the Springback of Commercially Pure Titanium in a Stretch Forming Operation

2015 ◽  
Vol 639 ◽  
pp. 107-114 ◽  
Author(s):  
Alan G. Leacock ◽  
Shane Quinn ◽  
Gregor Volk ◽  
David McCracken ◽  
Desmond Brown
Keyword(s):  
Stress State ◽  
Strain Rate ◽  
Pure Titanium ◽  
Commercially Pure Titanium ◽  
Stretch Forming ◽  
Commercially Pure ◽  
Strain And Strain Rate ◽  
Strain Magnitude ◽  
Cp Ti ◽  
Processing Stress

A common processing stress state used in the construction of sheet metal components is that of uniaxial tension/stretching. This work examines the stretching of CP-Ti over a rigid form tool using varying degrees of strain and strain rate. The degree of springback is shown to be influenced by the interaction of strain rate, strain magnitude and time following forming.

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.

Thermomechanical Response of Commercially Pure Titanium under Large Plastic Deformation at High Strain Rates

2012 ◽  
Vol 548 ◽  
pp. 174-178 ◽  
Author(s):  
Chong Yang Gao ◽  
Wei Ran Lu
Keyword(s):  
Pure Titanium ◽  
Optimal Solution ◽  
Optimization Method ◽  
Strain Rates ◽  
Commercially Pure Titanium ◽  
Thermomechanical Response ◽  
Commercially Pure ◽  
Different Temperatures ◽  
Cp Ti ◽  
Constitutive Parameters

By using a dislocation-based plastic constitutive model for hcp metals developed by us recently, the dynamic thermomechanical response of an important industrial material, commercially pure titanium (CP-Ti), was described at different temperatures and strain rates. The constitutive parameters of the material are determined by an efficient optimization method for a globally optimal solution. The model can well predict the dynamic response of CP-Ti by the comparison with experimental data and the Nemat-Nasser-Guo model.

scholarly journals Deformation Resistance and Recrystallization of Commercially Pure Titanium in the High Strain Rate Hot Deformation

1986 ◽  
Vol 72 (2) ◽  
pp. 321-328 ◽  
Author(s):  
Takehide SENUMA ◽  
Hiroshi YADA ◽  
Hirobumi YOSHIMURA ◽  
Hisaaki HARADA ◽  
Takuji SHINDO ◽  
...  
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Hot Deformation ◽  
High Strain ◽  
Pure Titanium ◽  
Deformation Resistance ◽  
Commercially Pure Titanium ◽  
Commercially Pure

The Effect of Strain Rate on the Plastic Deformation Mode of CP-Ti during Surface Nanocrystallization

2011 ◽  
Vol 675-677 ◽  
pp. 239-242
Author(s):  
Chun Huan Chen ◽  
Cheng Jin ◽  
Rui Ming Ren
Keyword(s):  
Plastic Deformation ◽  
Surface Layer ◽  
Strain Rate ◽  
Shot Peening ◽  
Pure Titanium ◽  
Deformation Mode ◽  
Rate Variation ◽  
Commercially Pure Titanium ◽  
Surface Nanocrystallization ◽  
Cp Ti

The effect of the strain rate on the surface nanocrystallization of titanium is investigated both theoretically and experimentally in this paper. The strain rate variation and stress distribution from surface to the interior of titanium during shot peening are estimated firstly using finite element method. Then shot peening experiment is carried out on a commercially pure titanium (CP-Ti) plate, and the obtained surface microstructures is characterized by transmission electron microscopy (TEM). Combining theoretical simulations and experimental observations, the effect of strain rate on the strain accommodation mechanism and plastic deformation mode are discussed. It is concluded that the strain rate and stress achieve the highest at the top surface layer of CP-Ti, and the strain rate decrease dramatically from the surface to the interior. The strain rate at the top surface layer is up to 104 s-1, which leads to superplastic deformation of Ti. There is no mechanical twin in the surface layer, instead, deformation lamella and adiabatic shear bands are the dominating microstructures. By means of rotation recrystallization, those deformation bands evolve to nanocrystallines.

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