Materials with a hexagonal close-packed (hcp) crystal structure such as Mg, Ti and Zr are being used in the transportation, aerospace and nuclear industry, respectively. Material strength and formability are critical qualities for shaping these materials into parts and a pervasive deformation mechanism that significantly affects their formability is deformation twinning. The interaction between...

An understanding of load sharing among constituent phases aids in designing mechanical properties of multiphase materials. Here we investigate load partitioning between the body-centered-cubic iron matrix and NiAl-type precipitates in a ferritic alloy during uniaxial tensile tests at 364 and 506 °C on multiple length scales by in situ neutron diffraction and crystal plasticity finite element mo...

The crystal-melt interfacial free energies of different crystal orientations and crystal forms for the hard-dumbbell systems have been calculated directly using a multistep thermodynamic perturbation method via nonequilibrium work measurements with a cleaving procedure. We found that for the plastic crystal phase, the interfacial free energies decrease as the reduced bond length L* increases an...

In general, thermodynamic admissibility requires isotropic materials develop reversible deformation induced anisotropy (RDIA) in their elastic stiffnesses. Taking the elastic potential for an isotropic material to be a function of the strain invariants, isotropy of the elastic stiffness is possible under distortional loading if and only if the bulk modulus is independent of the strain deviator ...

Plastic anisotropy may strongly affect the stress and strain response in metals subjected to multiaxial cyclic loading. This evolves due various microstructural features. We first use simple models study how such features result evolving plastic anisotropy. A subsequent analysis of existing distortional hardening highlights difference between stress- strain-driven models. Following this analysi...

Efficient and accurate simulation of the deformations in anisotropic metallic sheets requires a constitutive model and an accompanying algorithm at large strains which take into account the anisotropy of both the elastic and plastic material behaviors, as well as their evolution with plastic strains. Recently we proposed such a constitutive model based on continuum energy considerations, the Le...