Micromechanical modeling of deformation behavior of duplex type TNB alloy with a multi-scale modeling approach

Abstract

Room temperature deformation behavior of niobium-containing two-phase TiAl alloy has been investigated numerically using a two-scale micromechanical FE model. A polycrystal with duplex microstructure consisting of globular and lamellar grains is modeled with 3D unit cells that take into account specific volume fractions and orientations of the grains. The constitutive behavior of the α<SUB>2</SUB> and γ-phases is described by continuum mechanics based crystal plasticity model. Quantitative representations of microstructural details are obtained from the SEM analysis of a particular TNB alloy. The material parameters of the α<SUB>2</SUB> and γ-phases are initially taken from literatures and modified to fit the tensile behavior of the TNB alloy. The model provides an insight into the local variation of stresses and strains of the duplex microstructure consisting of globular and lamellar colonies. The role of dislocations and slip systems on the evolution of local plastic deformation is discussed.