Void Nucleation and Growth in Dual-Phase Steel 600 during Uniaxial Tensile Testing

2009 ◽  
Vol 40 (13) ◽  
pp. 3117-3127 ◽  
Author(s):  
G. Avramovic-Cingara ◽  
Ch.A.R. Saleh ◽  
M.K. Jain ◽  
D.S. Wilkinson
2012 ◽  
Vol 706-709 ◽  
pp. 2066-2071
Author(s):  
Chad Oliver ◽  
Randy J. Bowers ◽  
Daniel E. Green

The behaviour of dual phase steel tubes at 600, 780, and 980 MPa strength grades undergoing rotary draw bending and pressure sequence hydroforming is examined. Bending was performed using three different bend ratios. Principal strains were measured at several locations on each tube. It was found that the level of strain experienced by the tubes was independent of steel grade. The outcome of the bending process was stochastic in nature; for a given steel grade and bend ratio, some tubes were successfully formed, while others experienced failure. The proportion of failed tubes was found to increase with higher strength steel grades and tighter bend ratios. Metallographic samples from the extrados of the bent tubes revealed that many of the same microstructural features affecting strength and elongation in uniaxial tensile testing, namely martensite banding and non-metallic inclusions, affected dual phase steel tubes undergoing rotary draw bending. Additionally, a nanoindentation technique was investigated to determine the potential for more detailed microstructural characterization.


2021 ◽  
Vol 11 (8) ◽  
pp. 3378
Author(s):  
Jie Chen ◽  
Darby J. Luscher ◽  
Saryu J. Fensin

A void coalescence term was proposed as an addition to the original void nucleation and growth (NAG) model to accurately describe void evolution under dynamic loading. The new model, termed as modified void nucleation and growth model (MNAG model), incorporated analytic equations to explicitly account for the evolution of the void number density and the void volume fraction (damage) during void nucleation, growth, as well as the coalescence stage. The parameters in the MNAG model were fitted to molecular dynamics (MD) shock data for single-crystal and nanocrystalline Ta, and the corresponding nucleation, growth, and coalescence rates were extracted. The results suggested that void nucleation, growth, and coalescence rates were dependent on the orientation as well as grain size. Compared to other models, such as NAG, Cocks–Ashby, Tepla, and Tonks, which were only able to reproduce early or later stage damage evolution, the MNAG model was able to reproduce all stages associated with nucleation, growth, and coalescence. The MNAG model could provide the basis for hydrodynamic simulations to improve the fidelity of the damage nucleation and evolution in 3-D microstructures.


2002 ◽  
Vol 62 (1) ◽  
pp. 73-81 ◽  
Author(s):  
J. M. García Páez ◽  
A. Carrera ◽  
E. Jorge Herrero ◽  
I. Millán ◽  
A. Rocha ◽  
...  

2001 ◽  
Author(s):  
M. A. Haque ◽  
M. T. A. Saif

Abstract We present a MEMS-based technique for in-situ uniaxial tensile testing of freestanding thin films inside SEM and TEM. It integrates a freestanding thin film specimen with MEMS force sensors and structures to produce an on-chip tensile testing facility. Cofabrication of the specimen with force and displacement measuring mechanisms produces the following unique features: 1) Quantitative experimentation can be carried out in both SEM and TEM, 2) No extra gripping mechanism is required, 3) Specimen misalignment can be eliminated, 4) Pre-stress in specimen can be determined, and 5) Specimens with micrometer to nanometer thickness can be tested. We demonstrate the technique by testing a 200-nanometer thick Aluminum specimen in-situ in SEM. Significant strengthening and anelasticity were observed at this size scale.


2000 ◽  
Author(s):  
T. Jesse Lim ◽  
Wei-Yang Lu

Abstract In this work, uniaxial tensile testing of a 63Sn-37Pb alloy with different specimen sizes and aging conditions had been carried out. Although the stress-strain responses of different specimen sizes and aging conditions differs, the ultimate strength of the specimens with 16 hours, 100°C aging are similar for the sizes tested. The specimens with 25 days, 100°C aging have different stress-strain response with different sizes, and have a lower ultimate strength and higher failure strain compared to 16 hours, 100°C aging specimens.


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