Johnson-Cook based criterion incorporating stress triaxiality and deviatoric effect for predicting elevated temperature ductility of titanium alloy sheets

2017 ◽  
Vol 123 ◽  
pp. 94-105 ◽  
Author(s):  
Beatrice Valoppi ◽  
Stefania Bruschi ◽  
Andrea Ghiotti ◽  
Rajiv Shivpuri
Keyword(s):  
Titanium Alloy ◽  
Elevated Temperature ◽  
Stress Triaxiality

Stress Triaxiality in Chip Segmentation During High Speed Machining of Titanium Alloy

2014 ◽  
Author(s):  
Xueping Zhang ◽  
Rajiv Shivpuri ◽  
Anil K. Srivastava
Keyword(s):  
Titanium Alloy ◽  
High Speed ◽  
Split Hopkinson Pressure Bar ◽  
Shear Bands ◽  
Stress Triaxiality ◽  
Machining Process ◽  
High Speed Machining ◽  
Hopkinson Pressure Bar ◽  
Static Tests ◽  
Pressure Stress

Beside strain intensity, stress triaxiality (pressure-stress states) is the most important factor to control initiation of ductile fracture in chip segmentation through affecting the loading capacity and strain to failure. The effect of stress triaxiality on failure strain is usually assessed by dynamic Split Hopkinson Pressure Bar (SHPB) or quasi-static tests of tension, compression, torsion, and shear. However, the stress triaxialities produced by these tests are considerably different from those in high speed machining of titanium alloys where adiabatic shear bands (ASB) are associated with much higher strains, stresses and temperatures. This aspect of shear localization and fracture are poorly understood in previous research. This paper aims to demonstrate the role of stress triaxiality in chip segmentation during machining titanium alloy using finite element method. This research promotes a fundamental understanding of thermo-mechanics of the high-speed machining process, and provides a logical insight into the fracture mechanism in discontinuous chips.

Acoustic Emission Study on Effect of Stress Triaxiality on Damage Micromechanisms in Near Alpha Titanium Alloy

2009 ◽  
Vol 28 (2) ◽  
pp. 85-90 ◽  
Author(s):  
Jalaj Kumar ◽  
Sony Punnose ◽  
M. Mahesh Kumar ◽  
T. Jayakumar ◽  
Vikas Kumar
Keyword(s):  
Acoustic Emission ◽  
Titanium Alloy ◽  
Stress Triaxiality ◽  
Alpha Titanium ◽  
Emission Study ◽  
Acoustic Emission Study

scholarly journals Forming Features and Properties of Titanium Alloy Billets After Radial-Shear Rolling

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3179 ◽  
Author(s):  
Skripalenko ◽  
Galkin ◽  
Vladimirovich Karpov ◽  
Romantsev ◽  
Kaputkina ◽  
...  
Keyword(s):  
Computer Simulation ◽  
Titanium Alloy ◽  
Rolling Mill ◽  
Stress Triaxiality ◽  
Grain Structure ◽  
Structure Changes ◽  
Ring Shape ◽  
Accumulated Strain ◽  
Experimental Rolling ◽  
Radial Shear Rolling

Radial-shear rolling (RSR) of titanium alloy billets was realized in a three-high rolling mill. Experimental rolling was simulated using DEFORM software. The purpose was to reveal how stress-strain state parameters, grain structure and hardness vary along the billet’s radius in the stationary stage of the RSR process. It was also the goal to establish a relation between stress state parameters, hardness and grain structure. Changes in the accumulated strain and the stress triaxiality were established by computer simulation. Hardness and grain size changes were obtained after experimental rolling. The novelty aspect is that both computer simulation and experimental rolling showed that there is a ring-shape area with lowered strength in the billet’s cross-section. The radius of the ring-shape area was predicted as a result of the research.

Fracture of an α/β titanium alloy under stress triaxiality states at 773 K

1996 ◽  
Vol 34 (9) ◽  
pp. 1483-1490 ◽  
Author(s):  
M. Bourgeois ◽  
X. Feaugas ◽  
M. Clavel
Keyword(s):  
Titanium Alloy ◽  
Stress Triaxiality
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