Dresden 2026 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 7: Mechanical Properties and Alloy Design II

MM 7.6: Vortrag

Montag, 9. März 2026, 17:15–17:30, SCH/A215

Atomistic-to-Mesoscale Computational and Experimental Analysis of the Interactions between Dislocations, Precipitates, Grain and Phase Boundaries in Complex Alloys — •Liming Xiong — NC State University, Raleigh, NC, USA

In this talk, we will present multiscale computational and experimental analysis on the deformation behavior of complex alloys. In experiments, polycrystalline nickel, alloy 709, and Ni3Al-NiCr (γ/γ') alloys are deformed in a transmission electron microscope (TEM). Microstructure evolution is imaged through in-situ TEM. Local stress build up at the slip-GB/PBs are measured by electron backscattering diffraction (EBSD). Meanwhile, concurrent atomistic-continuum (CAC) simulations are performed to understand how a queue of dislocations interacts with the atomically structured precipitates, coherent twin boundaries (CTBs), GB, and γ/γ' PB. One unique feature of CAC is to accommodate the microscale slip containing a large population of dislocations together with the atomistic structure nearby the precipitates/GB/PBs all within one model. Our several findings are: (i) the sequential dislocation-precipitates differs from the single dislocation-precipitates. It is history dependent and has a mechanism cross-over from Orowan bowing out to cross-slip; (ii) the CTBs don't block dislocations. They can accommodate incoming dislocations by allowing them to migrate and form a pileup on the CTB; (iii) dislocation motion is smooth in γ phase but jerky in γ' phase. Such insight will support the design of high-performance alloys by configuring the precipitates, CTBs, GBs, and PBs in them appropriately.

Keywords: Precipitates; Grain Boundaries; Phase Boundaries; Dislocations; Atomistic and Multiscale Modeling