Strain rate effect on the tension and compression stress-state asymmetry for electron beam additive manufactured Ti6Al4V

The present experimental investigation lays the groundwork for coupling the plastic flow stresses of an Additive Manufactured (AM) Ti6Al4V with the corresponding strain hardening rate responses and fracture morphologies for this material at varying strain rates and stress states for the first time....

Full description

Saved in:
Bibliographic Details
Published in:Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 2018-01, Vol.713, p.125-133
Main Authors: Rodriguez, Omar L., Allison, Paul G., Whittington, Wilburn R., El Kadiri, Haitham, Rivera, Oscar G., Barkey, Mark E.
Format: Article
Language:English
Subjects:
Additives
Adiabatic flow
Asymmetry
Deformation mechanisms
Dependence
Dislocations
Electron beams
Electrons
Hardening rate
High strain rate
Inspection
Mechanical properties
Mechanical twinning
Morphology
Plastic flow
Shear localization
Strain hardening
Strain rate
Titanium base alloys
Video compression
Yield strength
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The present experimental investigation lays the groundwork for coupling the plastic flow stresses of an Additive Manufactured (AM) Ti6Al4V with the corresponding strain hardening rate responses and fracture morphologies for this material at varying strain rates and stress states for the first time. The macroscopic response was obtained under different stress states (uniaxial tension and compression) and deformation rates (ranging from quasi-static at 0.001s−1 to the high rate domain at 1500s−1) to elucidate the tension-compression asymmetry and strain rate dependence of the material. The results identified that, (a) compressive yield strengths are higher than their tensile counterparts and (b) the strength differential effect is more prominent under high strain rates. The mechanical behavior is explained in terms of deformation mechanisms reasoned from close inspection of strain hardening rate curves. Dislocation glide and mechanical twinning contribution as dominant plastic units were identified in stages and their relation with deformation mode and rate was established. Based on fractography analyses of the tensile samples, a rate dependence showed a shift from classic cup-cone fracture at quasi-static rates to fracture along the shear plane at high strain rates. The high strain rate compression samples also show an interesting fracture morphology with high speed video capturing adiabatic shear localization.
ISSN:0921-5093
1873-4936
DOI:10.1016/j.msea.2017.12.062