A method is proposed to identify the fully anisotropic elasticity tensor by applying the impulse excitation technique. A specially designed batch of several differently oriented bar-shaped specimens with rectangular cross section is analyzed with respect to the eigenfrequencies of their fundamental flexural and torsional modes. Estimations based on the equations for the calculation of the isotropic Young’s modulus and the shear modulus from the ASTM standard allow a first approximation of the elasticity tensor from a selected subset of the measured eigenfrequencies. Subsequently, a more precise determination of the elasticity tensor is achieved by a numerical modal analysis using the finite element method. In this course, a Newton–Raphson optimization method is applied to solve the inverse problem. The proposed approach is demonstrated on a batch of specimen fabricated from the nickel-base alloy IN718 by selective laser melting.

Additive manufacturing of metallic materials generates strong crystallographic textures, leading to anisotropic elastic properties on the macroscopic scale. The impact of the processing parameters on the resulting texture requires suitable techniques for the prediction and the experimental determination of elastic properties to exploit the anisotropy in the design process. Within this study mechanical as well as microstructure based approaches are applied on a batch of specimens manufactured from IN718 by selective laser melting to assess the elastic behavior on macroscropic scale. Tensile loading experiments and the impulse excitation technique are applied for the determination of elastic properties without additional constitutive data. Furthermore, the elastic behavior is estimated from single-crystal elastic properties and texture data measured by electron backscatter diffraction and high energy X-ray diffraction. The results of the applied approaches are discussed and compared, allowing also to assess the homogeneity of the elastic properties within the batch of specimens.

Reinforcing steel bars (rebars) are widely manufactured using the Tempcore™ process. Several studies have been conducted analyzing the effect of the heat treatment route on the strength and corrosion resistance of rebars, but knowledge of its effects on the residual stresses of the finished product are largely lacking. This paper presents experimental investigations to identify the material parameters necessary to simulate the Tempcore™ process using thermo-elasto-plastic constitutive modeling in order to study the generation of residual stresses during the manufacturing process. Mechanical parameters such as yield strength at elevated temperatures and elastic constants were determined experimentally. A continuous cooling transformation diagram needed to model the phase transformations was also identified and is presented here. Residual stress distributions in the surface region of the rebar were characterized using X-ray diffraction. Further characterizations of microstructure, chemical composition, and hardness were carried out. The constitutive modeling approach for the numerical simulation is briefly described for which the experimentally determined parameters are required as input.