Role of crystallographic orientation on intragranular void growth in polycrystalline FCC materials

Paul Christodoulou (1) , Sylvain Dancette (2) , Ricardo Lebensohn (3) , Eric Maire (2) , Irene Beyerlein (1)

1 UC Santa Barbara - University of California [Santa Barbara]
2 MATEIS - Matériaux, ingénierie et science [Villeurbanne]
3 LANL - Los Alamos National Laboratory

In this work, we study the effect of crystallographic orientation and applied triaxiality on the growth of intragranular voids. Two 3D full-field micromechanics methods are used, the dilatational visco-plastic fast-Fourier transform (DVP-FFT) and the crystal plasticity Finite Elements (CP-FE), both of which incorporate a combination of crystalline plasticity and dilatational plasticity. We demonstrate with several select cases that predictions of void growth from both formulations agree qualitatively. With the more computationally efficient DVP-FFT, additional effects of polycrystalline microstructure and the influence of nearest neighborhood are investigated. Crystals bearing a single intracrystalline void are studied in three types of 3D microstructural environments: isolated single crystals, individual equal-sized grains within a regular polycrystal, and individual variable sized grains within a polycrystal with grains and voids randomly located. We show that loading type plays a significant role. In strain-rate controlled conditions, voids in the hardest [111]-crystals grow the fastest in time, whereas in stress-controlled conditions, voids in the softest [100]-crystal grow the fastest in time. The analysis reveals that on average void growth is slower for the same starting orientation in the polycrystal than in the single crystal. We find that at the highest triaxiality tested that the correlation between crystal orientation and void growth rate in the polycrystal strengthens, drawing closer to that seen in the isolated single crystals. These results and model can help guide the microstructural design of polycrystalline materials with high strength and damage-tolerance in high-rate deformation.

Mots clés: Voids and inclusions; Polycrystalline material; Crystal plasticity; Viscoplastic material; Finite elements

Domaines: Mécanique des matériaux [physics.class-ph]

Paul Christodoulou, Sylvain Dancette, Ricardo Lebensohn, Eric Maire, Irene Beyerlein. Role of crystallographic orientation on intragranular void growth in polycrystalline FCC materials. International Journal of Plasticity, 2021, 147, pp.103104. ⟨10.1016/j.ijplas.2021.103104⟩. ⟨hal-03342622⟩