Role of grain boundary structure on diffusion and dissolution during Ni/Al nanolaminate combustion

2020 ◽  
Vol 127 (12) ◽  
pp. 125111 ◽  
Author(s):  
Brandon Witbeck ◽  
Douglas E. Spearot
Keyword(s):  
Grain Boundary ◽  
Boundary Structure ◽  
Grain Boundary Structure

Grain boundary structure intergranular fracture and the role of segregants as embrittling agents

1980 ◽  
Vol 295 (1413) ◽  
pp. 165-165 ◽  
Keyword(s):  
Grain Boundary ◽  
Intergranular Fracture ◽  
Boundary Region ◽  
Boundary Structure ◽  
Orientation Relation ◽  
Substantial Evidence ◽  
Grain Boundary Structure ◽  
Different Types

There is substantial evidence, from studies of annealed and crept aluminium, which indicates that once a dislocation has entered the boundary region between two grains it dissociates to form several grain boundary dislocations of Burgers vectors determined by the orientation relation between the grains. Subsequent behaviour depends on boundary structure, the dissociation products remaining bunched together in certain boundaries and moving apart in others, indicative of a friction type stress active in the boundary. A simple classification of the different types of boundary, where friction stresses were either high or low, into coincidence and non-coincidence boundaries, however, was not possible.

Atomistic Simulation of Grain Boundary Structure and Diffusion in B2 NiAl

1996 ◽  
Vol 458 ◽  
Author(s):  
Yuri Mishin ◽  
Diana Farkas
Keyword(s):  
Grain Boundary ◽  
Atomistic Simulation ◽  
Effective Activation Energy ◽  
Correlation Effect ◽  
Boundary Structure ◽  
Self Diffusion ◽  
Embedded Atom ◽  
Grain Boundary Structure ◽  
And Diffusion

ABSTRACTUsing embedded atom potentials and molecular statics we calculate the structure and energy of [001] tilt grain boundaries in NiAl for 25 orientations with Σ values from 5 to 185. For three structures (stoichiometric, Ni-rich and Al-rich) of the Σ = 5 (210) boundary we simulate tracer self-diffusion by the vacancy mechanism both parallel and perpendicular to the tilt axis using the Monte Carlo technique. The effective activation energy calculated in a wide temperature range is compared with the spectrum of individual jump energies in the boundary core. The results are interpreted in terms of the grain boundary structure-diffusion relationship and the role of the jump correlation effect in grain boundary diffusion.

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