Cooperative grain boundary sliding in nanocrystalline materials

Abstract

Employing a recent modeling scheme for grain boundary sliding [Zhao et al. Adv. Eng. Mater. 2017, doi:10.1002/adem.201700212], crystallographic textures were simulated for nanocrystalline fcc metals deformed in shear compression. It is shown that, as grain boundary sliding increases, the texture strength decreases while the signature of the texture type remains the same. Grain boundary sliding affects the texture components differently with respect to intensity and angular position. A comparison of a simulation and an experiment on a Pd-10 atom % Au alloy with a 15 nm grain size reveals that, at room temperature, the predominant deformation mode is grain boundary sliding contributing to strain by about 60%.

Ductile vs. brittle behavior of pre-cracked nanocrystalline and ultrafine-grained materials

“…It should be noted that there are several examples of nanomaterials showing both superior strength and good ductility at room temperature or even superplasticity at elevated temperatures [20,30,33,[64][65][66][67][68][69][70][71][72][73][74][75][76][77][78][79]. In these examples, good ductility/superplasticity is exhibited by UFG ceramics [62][63][64][65][66] and metallic materials [30,33,76,78,79] (with the mean grain size ranging from 100 nm to 1 lm) as well as by nanocrystalline ceramics [71,72,75] and metallic materials [1,20,[67][68][69][70]73,74,77] (with the mean grain size ranging from 5 to 100 nm).…”

Deformation twinning in nanocrystalline materials

“…Grain boundary sliding in nc materials was first observed by MD simulations [24,36,37,105], later reported experimentally [27,[106][107][108], and modeled analytically [109][110][111][112]. Importantly, such grain boundary sliding may occur in a coordinated way [27,[105][106][107][113][114][115].…”

“…Importantly, such grain boundary sliding may occur in a coordinated way [27,[105][106][107][113][114][115]. For example, shown in Fig.…”

Atomistic Insights on the Wear/Friction Behavior of Nanocrystalline Ferrite During Nanoscratching as Revealed by Molecular Dynamics

“…Figure 10 illustrates an example of grain boundary sliding observed for the sample with D = 58.8 Å . Several theoretical [50][51][52][53] and experimental [54][55][56] studies have shown that GBs sliding is one of the primary deformation mechanisms that occur upon grain refinement in nanosized polycrystalline material. In the work of Mishra et al [18], it was reported that GB sliding was the main deformation mechanism during nanomachining of nanocrystalline silicon carbide.…”