Segregation-Induced Nanofaceting Transition at an Asymmetric Tilt Grain Boundary in Copper

NJ Peter and T Frolov and MJ Duarte and R Hadian and C Ophus and C Kirchlechner and CH Liebscher and G Dehm, PHYSICAL REVIEW LETTERS, 121, 255502 (2018).

DOI: 10.1103/PhysRevLett.121.255502

We show that chemistry can be used to trigger a nanofaceting transition. In particular, the segregation of Ag to an asymmetric tilt grain boundary in Cu is investigated. Aberration-corrected electron microscopy reveals that annealing the bicrystal results in the formation of nanometer-sized facets composed of preferentially Ag-segregated symmetric Sigma 5210 segments and Ag-depleted 230/100 asymmetric segments. Our observations oppose an anticipated trend to form coarse facets. Atomistic simulations confirm the nanofacet formation observed in the experiment and demonstrate a concurrent grain boundary phase transition induced by the anisotropic segregation of Ag.

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