Ohio University, USA

E-mail:wang.363@osu.edu

Research Interests

Prof. Wang’s research projects focus on the development of computational models and simulation techniques, validated by experimentation, for fundamental understanding of mechanisms underlying microstructural evolution during phase transformations and plastic deformation, design of novel microstructures through non-conventional transformation and deformation pathways, and practical applications to microstructural engineering of advanced materials. Current research areas include

  • Energetics and kinetics of elementary defects and defect processes in crystalline and amorphous solids
  • Microstructure development during structural phase transformations and microstructure–dislocation interactions during exposure to temperature and stress (including processing conditions under additive manufacturing and friction welding) in advanced structural materials including high-temperature Ni-base superalloys, high strength steels, and light alloys (Ti-,  Al- and Mg-alloys)
  • Phase transformations and microstructural evolution in shape memory alloys
  • Structural non-uniformity, extended defects, shear banding and deformation mechanisms in metallic glasses
  • Grain growth and texture development in polycrystalline materials during annealing including static and dynamic recrystallization
  • Interdiffusion microstructure and diffusion path in multi-component and multiphase coatings and multi-layers
  • Segregation and segregation transition at extended defects (dislocations and grain boundaries) and migration of interfaces and dislocations with segregating defects and precipitates

Teaching Interests

  • Computational Materials Science and Engineering
  • Thermodynamics and Kinetics
  • Phase Transformations
  • Defects and Microstructures

Highlights of Research Accomplishments

Prof. Wang is an internationally recognized expert on fundamental and applied research in the field of computational materials modeling. He is at the forefront in the development and application of the phase field theory and modeling techniques to phase transformations, interdiffusion, grain growth, and dislocation processes in materials. The phase field approach has achieved increasing prominence in the field of computational materials science and engineering, and Prof. Wang has been one of the principal developers and practitioners of this technique. In his core research he develops and advances the method for new scientific and technical challenges, and through his collaborations he integrates multiscale modeling techniques with advanced experimental characterization to develop computational design tools for applications to specific materials systems and problems. His innovative work includes:

  • Development and dissemination of Diffusive Molecular Dynamics (DMD) method and its applications to study atomistic mechanisms of dislocation climb and void growth. These works reveal, for the first time, a complete atomistic description of coupled displacive-diffusional processes that take place during (a) creep deformation governed by dislocation climb and (b) microscopic void growth by simultaneous diffusive accumulation of vacancies and dislocations emission. Because of the time-scale limitation, conventional molecular dynamics (MD) has not been able to capture these processes.
  • Development of a heterogeneously randomized shear transformation zone (STZ) model and a nanoscale kinetic Monte Carlo (kMC) algorithm to study strain localization and extreme value statistics during deformation of bulk metallic glasses (BMGs). The distinct features of the model, compared to previous work, are (a) the introduction of randomized event catalogs for different nanoscale volume elements, repeated operations within the same element and (b) a “generation-dependent” softening term to reflect the internal structural change after each deformation.
  • Integration of the phase field method with ab inito calculations of the generalized stacking fault (GSF) energy and multi-plane GSF (MGSF). This work has led to the development of the microscopic phase field model (MPF) of nano-mechanics, which has opened a new avenue for the study of elementary defects and defect processes such as core energy, structure and Peierls stress of dislocations and transformation dislocations, and slip transmission of dislocations across interphase interfaces.
  • Application of transition pathway search algorithms such as the nudged elastic band (NEB) method to ab initio informed MPF Hamiltonian for quantitative characterization of activation pathway (activation energy of nucleation and critical configuration of nucleus) of various elementary defect processes involved in solid-state phase transformations and plastic deformation. These are critical parameters for quantitative description of materials processing and performance but extremely difficult to obtain by experiment.
  • Integration of phase field method with fast Fourier transform (FFT) based crystal plasticity model for co-evolution of dislocation density and micromechanical fields and grain and precipitate microstructures and structural and diffusional fields.
  • Application of the phase field method at mesoscale to study the collective behaviour of mutually interacting defects of arbitrary configurations in both elastically anisotropic and inhomogeneous systems. 
  • Integration of the phase field method with CALPHAD thermodynamic and mobility databases, which has allowed for the development of the phase field methods into engineering design tools for practical industrial applications.
  • Development and application of phase field models for interdiffusion microstructure in high-temperature coatings and oxidation resistant alloys.
  • Development and applications of phase field models for texture development and grain growth in polycrystalline materials.
  • Theory and simulation of impurity segregation and transition at grain boundaries and dislocations. The work for the first time formulated a complete continuum segregation model based on gradient thermodynamics and contrasted the model to preexisting continuum and discrete models.
  • Incorporation of crystallography and coherency elastic strain energy into the phase field approach, which made the method applicable to an important class of phase transformations in materials science and engineering, the solid-state phase transformations.

Publications

Over 140 refereed journal articles (including 80 published in Acta Mater.) with over 4200 citations. Among them 37 publications have 37+ citations each (ISI), i.e., H-index = 37.