A finite element approach to study the influence of cast pores on the mechanical properties of the Ni-base alloy MAR-M247

A volume element model representing the microstructure of porous MAR-M247 is presented which is used to study the influence of cast pores on effective mechanical properties. To ensure a realistic representation of the material, porous cast samples are analyzed by computed tomography scans. The modeling approach pursues an automated microstructure generation based on simple but flexible synthetic pore geometries which is advantageous for parametric studies, e.g. exploring the influence of a varying pore volume fraction and different pore morphologies. The effective Young's modulus, the effective shear modulus and the onset of plastification predicted by finite element simulations of these volume element models provide an indication of the influence of the characteristics of the porosity on the material behavior: whereas for the elastic material properties the pore volume fraction is the major factor, plastic behavior is very sensitive to the actual pore morphology and distribution. To incorporate the results gained on the microscopic scale into numerical simulations of actual components a sequential scale coupling approach is proposed. An exemplary finite element analysis of a porous tensile test specimen using such an approach is shown.