Influence of defects on mechanical properties of bicrystal copper grain boundary interfaces

Abstract

Defects play a key role in the determination of material properties, especially at small scales. The influence of several kinds of defects (point vacancies, line vacancies and cracks) on the deformation and fracture characteristics of a planar copper grain boundary interface with a 45° lattice misorientation is explored using molecular dynamics simulations and the embedded-atom method. Both tensile and shear modes of interfacial separation are considered. The results show that the crystalline defects can have a strong influence on the interfacial behaviours. The sensitivity of the mechanical properties of the interface to a defect type may be different under tension than under shear. It is found that some defect topologies can improve certain properties (e.g. strength and fracture strain) of the bicrystal interface system.

Influence of Defects During the Tensile Deformation of Cu–Al Joint Interfaces at the Nano Scale

“…This conclusion is analogous to that of the copper interface in Ref. [36]. The level of stress oscillation in all three cases is weaker than that of the pristine interface system, which can be attributed to the decrease in interface rigidity due to the existence of point vacancy defects.…”

“…The peak stress is nearly half that of a pure copper bicrystal interface in Ref. [36], suggesting that the heterogeneous bonding between Cu and Al is weaker than that of a copper grain boundary interface. Similar to the behaviors of the copper interface, 24 36 an elastic springback stress oscillation associated with vibration of the model is observed after the occurrence of the peak stress at a displacement of about 0.6 nm.…”

Materials for future gas turbine applications

“…14,15 For more extreme conditions exploring high strain rate behaviour, X-FEL beam line experiments, such as those at SLAC in Stanford can be conducted that allow diffraction imaging of impact events at a temporal resolution of y10 214 seconds, in the imaging burst light can only travel few microns. This is more than adequate to explore the interplay between twinning and dislocations under high and medium rate loading where the twin growth velocity is y10 km s 21 .…”

“…16,17,18,19 The value of modelling from atomistic, including quantum mechanical effects, through to crystal level approaches is maturing quickly and has already had a direct impact on industry. This includes fields as diverse as cold dwell fatigue in aerospace titanium alloys, 20,21 the prediction of the magnetic transition in iron 22 and quantitative predictive capability for the elastic field trapping of dislocation loops in metals post irradiation damage 23 and the behaviour of interstitials. 24,25 It is important to recognise that physically based models may also play a critical role in being able to extract any meaningful quantitative data from some of the experimental methods.…”

Nanoscale interface of metals for withstanding momentary shocks of compression

“…[10][11][12] Molecular dynamics (MD) simulation, which is promising, has been used widely to describe the fundamental mechanical properties of nanocrystalline materials. 8,[13][14][15] Wang et al 14 studied the influence of defects on mechanical properties of the copper grain boundary interface, and they showed the interfacial behaviors subjected to tensile or shear strain were sensitive to crystalline defects. Spearot et al 15 used MD simulation to study the tensile strength of <100> and <110> tilt copper interfaces, which indicated that the two critical attributions of the interface structure were crystalline in orientation and certain structural units.…”