Characterization of Macroscopic Mechanical Anisotropy of Magnetocaloric Gadolinium Cylinders

The metallographic analysis of polycrystalline gadolinium cylinders revealed a microstructural anisotropy of some included phases in the extrusion and extrusion transversal directions. The amount of those phases in the material is not significant. However, the macroscopic anisotropy of mechanical properties needs to be verified. The strain distribution during compression loading was analyzed using finite element model (FEM) simulations. A FEM for the simulation of the elasto-plastic response of the Gd cylinders was performed. For this purpose, the experimentally obtained typical flow curve in the extrusion direction was used as the input data for the FEM model. Based on the dimensional similarity of the FEM model and the measured specimens, the potential appearance of macroscopic anisotropy is evaluated. Mechanical testing using compression cigar tests, as well as FEM, did not confirm any obvious effect of the elongated inclusions on the mechanical anisotropy of the gadolinium specimens.