ORALS

Porous metals are used in a wide range of applications because of the several advantages they have over non-porous metals which include low density, high energy absorption capability, and so on [1]. Among the porous metals, porous magnesium (Mg) with parallel cylindrical pores exhibits a higher energy absorption capability compared to porous light metals with isotropic pores [2, 3]. The microstructure of this porous Mg shows several distinctive features: elongated pores in the solidification direction, elongated coarse grains in the solidification direction, and a peculiar crystallographic texture where one of the normal directions of the {10-13} planes is closely oriented to the solidification direction. In the previous research [2], crystal plasticity analysis estimated that the different deformation modes were activated depending on loading direction which led to anisotropic deformation behavior. Furthermore, more detailed numerical investigations were performed to clarify the underlying mechanism for high energy absorption capability of this porous Mg [3]. This suggested significant contribution of texture development triggered by intra-granular misorientations. Based on the understanding of the deformation mechanism from the viewpoint of crystal plasticity, a possible strategy for further improvement of energy absorption properties by pre-loading was also proposed [3]. In this study, the influence of the initial texture on energy absorption capability in porous Mg with oriented pores is summarized based on a series of crystal plasticity finite element calculations. Implemented deformation modes in the present numerical method are the basal slip, prismatic slip, first order pyramidal <<b>a</b>> slip, second order pyramidal <<b>c</b>+<b>a</b>> slip, and {10-12} tensile twinning systems. The analysis models, which reproduce elongated pore structure, grain morphology, and initial texture, were constructed based on microstructural observations [2, 3]. The results of numerical calculations showed significant dependence of initial texture on energy absorption capability.

References:
[1] L.-P. Lefebvre, J. Banhart, D. C. Dunand, Porous metals and metallic foams: Current status and recent developments. Adv. Eng. Mater. 10 (2008) 775-787.\n[2] M. Tane, T. Mayama, A. Oda, H. Nakajima, Effect of crystallographic texture on mechanical properties in porous magnesium with oriented cylindrical pores. Acta Mater. 84 (2015) 80-94.\n[3] T. Mayama, M. Tane, Y. Tadano, Superior energy absorption in porous magnesium: Contribution of texture development triggered by intra-granular misorientations. Acta Mater. 165 (2019) 62-72.