Microstructural Development around Crater in Commercial Pure Titanium

2016 ◽  
Vol 849 ◽  
pp. 238-244
Author(s):  
Ying Chao Li ◽  
Bo Long Li ◽  
Tong Bo Wang ◽  
Zhen Qiang Wang ◽  
Zuo Ren Nie
Keyword(s):  
Electron Backscatter Diffraction ◽  
Adiabatic Shear Band ◽  
Shear Bands ◽  
Pure Titanium ◽  
Adiabatic Shear ◽  
Microstructural Development ◽  
Adiabatic Shear Bands ◽  
Titanium Plate ◽  
Commercial Pure Titanium ◽  
Backscatter Diffraction

The commercial pure titanium plate was shot vertically by the projectile with a diameter of 7.62mm at impact velocities ranging from 782m/s to 825m/s. The microstructure around the crater of commercial pure titanium plate was analyzed by optical microscopy (OM) and electron backscatter diffraction (EBSD) methods. It was found that different microstructures were observed along the depth of cater. In upper region of the crater, grains were deformed and fragmented. Adiabatic shear bands (ASBs) were observed in the middle of the crater, and some ASBs were bifurcated. At the bottom of the crater, the grains were less deformed, and the deformation twins were formed. The microstructures in the center of adiabatic shear band were mainly consisted of the dynamic recrystallization grains and sub-grains. The microstructure in the transition region was elongated grains along the shear stress distribution.

Analysis and characterization by electron backscatter diffraction of microstructural evolution in the adiabatic shear bands in Fe–Cr–Ni alloys

2009 ◽  
Vol 24 (8) ◽  
pp. 2617-2627 ◽  
Author(s):  
Huajie Yang ◽  
Yongbo Xu ◽  
Yasuaki Seki ◽  
Vitali F. Nesterenko ◽  
Marc André Meyers
Keyword(s):  
Microstructural Evolution ◽  
Electron Backscatter Diffraction ◽  
Shear Bands ◽  
Adiabatic Shear ◽  
Adiabatic Shear Bands ◽  
Localized Deformation ◽  
Ni Alloys ◽  
Electron Backscatter ◽  
Backscatter Diffraction ◽  
Equiaxed Grains

The microstructural evolution inside adiabatic shear bands in Fe–Cr–Ni alloys dynamically deformed (strain rates > 104 s−1) by the collapse of an explosively driven, thick-walled cylinder under prescribed strain conditions was examined by electron backscatter diffraction. The observed structure within the bands consisted of both equiaxed and elongated grains with a size of ∼200 nm. These fine microstructures can be attributed to recrystallization; it is proposed that the elongated grains may be developed simultaneously with localized deformation (dynamic recrystallization), and the equiaxed grains may be formed subsequently to deformation (static recrystallization). These recrystallized structures can be explained by a rotational recrystallization mechanism.

scholarly journals Phenomena of Adiabatic Shear Bands Forming of Structural Steels Under Impact Load Conditions

2020 ◽  
Vol 50 (2) ◽  
pp. 315-337
Author(s):  
Michał Gmitrzuk ◽  
Lech Starczewski
Keyword(s):  
Electron Backscatter Diffraction ◽  
Impact Load ◽  
Shear Bands ◽  
Adiabatic Shear ◽  
Adiabatic Shear Bands ◽  
High Speeds ◽  
Impact Forces ◽  
Deformation Speed ◽  
Backscatter Diffraction ◽  
Ebsd Method

AbstractThe paper presents the results of an experimental study on adiabatic shear bands (ASB) in two grades of steel with three different microstructures. Samples were subjected to impact forces in order to obtain a targeted shear band. The process of deforming the samples was carried out with a bar impact rod moving at high speeds in the range of 1.4 m/s to 16.5 m/s was carried out. Microstructural studies of deformed samples were performed using the Electron Backscatter Diffraction (EBSD) method. The results of the experiments show that the ASB type depends on the initial microstructure of the material and the deformation speed. It has been shown that, depending on the type of microstructure, ASBs are characterized by a different mechanism of formation and show different character.

Predeformation Effects on Shear Response and Microstructure in Pure Titanium-TA2

2007 ◽  
Vol 546-549 ◽  
pp. 1409-1412
Author(s):  
Shu Hua Li ◽  
Fu Chi Wang ◽  
Cheng Wen Tan ◽  
Zhi Yong Chen ◽  
Zhi Sun
Keyword(s):  
Shear Bands ◽  
Pure Titanium ◽  
Adiabatic Shear ◽  
Transmission Electron Micrograph ◽  
Adiabatic Shear Bands ◽  
Hopkinson Pressure Bar ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Diffraction Patterns ◽  
Pressure Bar

Adiabatic shear properties of pure titanium-TA2 have been investigated using specially designed specimen in a Hopkinson pressure bar at high strain rate of 103s- 1. Microstructural characteristics was investigated using scanning electrion microscopy as well as transmission and high resolution transmission electrion microscopy .The results showed that the shear stress and adiabatic sensitivity for rolled 45% TA2 are higher than forged TA2. Comparing the adiabatic shear bands (ASB) both in the forged and rolled TA2, no evidence in morphology alteration was found except to shear band widths. The transmission electron micrograph of the ASB in forged and rolled TA2 showed the grain size reduction from ~20μm to 200nm. No deformation twins have been observed in ASB. The selected area electron diffraction patterns of the ASB showed reflections of multiple grains, forming discontinuous rings which can be indexed as h.c.p. structure of α-Ti. This indicates that the ASB consists of fine grains of α-Ti and the α-Ti→ β-Ti transformation did not occur.

Penetration Damaging Behavior of TB17 Titanium Alloy

2020 ◽  
Vol 993 ◽  
pp. 100-107
Author(s):  
Jing Li ◽  
Yun Peng Xin ◽  
Tao Jiang ◽  
Xin Nan Wang ◽  
Zhi Shou Zhu
Keyword(s):  
Titanium Alloy ◽  
Adiabatic Shear Band ◽  
Shear Bands ◽  
High Strength ◽  
Adiabatic Shear ◽  
Adiabatic Shear Bands ◽  
Internal Wall ◽  
Micro Cracks ◽  
Opening Stage ◽  
River Pattern

The damage behavior of TB17 titanium alloy with ultra-high strength was studied by 12.7mm diameter armor piercing test. The characteristics and mechanism of damaging were analyzed by the observation of damage morphology of target board. The results indicated that the area was irregular at the opening stage, the internal wall were turtle-shell-like or poly-porous, a few cracks and no adiabatic shear band was observed. The zone was parabolic at the penetrating stage, the internal wall were granular or river pattern, adiabatic shear bands and fragments existed around the crater. A large number micro-pores and micro-cracks originating from the adiabatic shear bands expanded and formed macroscopic cracks. Finally, the target board fractured.

Effects of Initial Micro-Structures on Deformation Behaviors of Commercial Pure Titanium

2016 ◽  
Vol 879 ◽  
pp. 2050-2054
Author(s):  
Tong Bo Wang ◽  
Bo Long Li ◽  
Mian Li ◽  
Zuo Ren Nie
Keyword(s):  
Shear Band ◽  
Adiabatic Shear Band ◽  
Deformation Characteristic ◽  
Pure Titanium ◽  
Adiabatic Shear ◽  
Dislocation Boundary ◽  
Shear Sensitivity ◽  
Commercial Pure Titanium ◽  
Deformation Behaviors ◽  
Micro Structures

In this paper, effects of initial micro-structures on deformation behaviors of commercial pure titanium were elaborated by investigating the evolution of dislocation boundary and its adiabatic shear sensitivity. At the low to medium stain rates, the main plastic deformation mechanism of as-annealed commercial pure titanium is dislocation slipping. Meanwhile, geometrically necessary boundaries (GNBs) with different directions are generated and crossed with each other. However, new dislocation boundaries are formed in as-cold rolled plates, which are parallel to the initial ones induced by cold rolling. When the strain rate is up to 1000 s-1, the initial dislocation boundary playes an adverse role in the adiabatic shear sensitivity of commercial pure titanium. The adiabatic shear band is the high-speed deformation characteristic micro-structure in commercial pure titanium. In addition, dynamic recrystallized grains are generated in the center of an adiabatic shear band, which is consistent with the sub-grain rotation mechanism.

Adiabatic Shear Localization in High Speed Cutting of Hardened Steel

2011 ◽  
Vol 55-57 ◽  
pp. 983-987 ◽  
Author(s):  
Chun Zheng Duan ◽  
Wei Sen Kong ◽  
Zhao Xi Wang ◽  
Min Jie Wang
Keyword(s):  
Shear Band ◽  
High Speed ◽  
Adiabatic Shear Band ◽  
Shear Bands ◽  
Cutting Speed ◽  
Shear Localization ◽  
Adiabatic Shear ◽  
Adiabatic Shear Bands ◽  
High Speed Cutting ◽  
Serrated Chips

The formation and development of adiabatic shear localization in serrated chips have great significance to study of mechanism of high speed cutting. This paper investigates the theory prediction and experimental verification of the critical cutting speed of adiabatic shear localization, distribution of adiabatic shear band in serrated chip and the geometry of adiabatic shear band during high speed cutting of hardened steel. The results indicated that the theoretical prediction of critical cutting speed is consistent with the experimental results.With the increase of cutting speed, the width and spacing of adiabatic shear bands in the serrated chips decrease linearly. There are two types of adiabatic shear bands during the formation and development of adiabatic shear localization, i.e. the deformation shear band and the transformed shear band.

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