Numerical investigation of mechanical properties of aluminum-copper alloys at nanoscale

Abstract

Nanoindentation is a powerful tool capable of providing fundamental insights of material elastic and plastic response at the nanoscale. Alloys at nanoscale are particularly interesting as the local heterogeneity and deformation mechanism revealed by atomistic study offers a better way to understand hardening mechanism to build a stronger material. In this work, nanoindentation in Al-Mg alloys are studied using atomistic simulations to investigate the effects of loading direction, alloying percentages of Mg via dislocation-driven mechanisms. Also, finite element (FE) nanoindentation simulations are performed using MD tensile test results as input parameters for the FE simulations. Material properties, such as hardness and reduced modulus, are computed from both the FE and MD simulations and then compared. Considering the fundamental difference between these two numerical approaches, the FE results obtained from the present study conform fairly with those from MD simulations. This paves a way into finding material properties of alloys with reduced simulation time and cost by using FE instead of MD. The results have been presented as load-displacement analysis, dislocation density, dislocation loops nucleation and propagation, von-Mises stress distribution and surface imprints. The techniques adopted in this paper to incorporate atomistic data into FE simulations can be further extended for finding other mechanical and fracture properties for complex alloy materials.

Using Molecular Dynamic Simulation to Understand the Deformation Mechanism in Cu, Ni, and Equimolar Cu-Ni Polycrystalline Alloys

“…On the other hand, molecular dynamics simulation of the Cu-Sb alloy shows that the formation of unstable stacking faults near the solute atoms leads to the softening of the alloy [8,9]. It has also been reported that the addition of aluminum as a solid solution in the copper structure makes the cross slip during the deformation easier, which causes the work hardening to be dependent on the strain rate [10,11]. In the study of copper alloy deformation, Szczerba et al [12] emphasized the dual role of material stacking fault energy on the activation of twinning and twinning stress of face-centered cubic (FCC) materials.…”

Nanoparticles reinforced Al-matrix composites fabricated by combination of pre-distribution and deformation: A review

“…The increased strength results in the seriously decreased plasticity and machinability with the addition of the particles into the matrix alloys. The ductility is maintained or increased of the AMCs when the particles decrease to nano-size [17][18][19][20]. However, the nano-sized particles are difficult to distribute homogeneously in Al-matrix [21][22][23][24].…”