Strengthening Behavior and Tension–Compression Strength–Asymmetry in Nanocrystalline Metal–Ceramic Composites

Abstract

Metal-ceramic composites are an emerging class of materials for use in the nextgeneration high technology applications due to their ability to sustain plastic deformation and resist failure in extreme mechanical environments. Large scale molecular dynamics simulations are used to investigate the performance of nanociystalline metal-matrix composites (MMCs) formed by the reinforcement of the nanociystalline Al matrix with a random distribution of nanoscale ceramic particles. The interatomic interactions are defined by the newly developed angular-dependent embedded atom method (A-EAM) by combining the embedded atom method (EAM) potential for Al with the Stillinger-Weber (SW) potential for Si in one functional form. The molecular dynamics (MD) simulations are aimed to investigate the strengthening behavior and the tension-compression strength asymmetiy of these composites as a function of volume fraction of the reinforcing Si phase. MD simulations suggest that the strength of the nanocomposite increases linearly with an increase in the volume fraction of Si in the Al-rich region, whereas the increase is very sharp in the Si-rich region. The higher strength of the nanocomposite is attributed to the reduced sliding/rotation between the AllSi and the Si/Si grains as compared to the pure nanociystalline metal.

Mechanical behaviors of nanocrystalline Cu/SiC composites: An atomistic investigation

“…Metal matrix nanocomposites (MMNs), which are reinforced by ceramic components (SiC, Al 2 O 3 , etc. ), have an extensive use in high technology applications [1] due to their high specific stiffness, high plastic flow strength, creep resistance, good oxidation and corrosion resistance [2][3][4]. To maximize the performance and reliability of such materials, a fine-tuning of the nanostructure is required.…”

“…The introduction of the reinforcement leads to the hardness increase of the Cu/Al 2 O 3 nanocomposites remarkably [5]. However, it is still significantly difficult and expensive to implement nanoscale experiments due to heterogeneous nature of interfaces in nanocomposites and small time scales of the relevant processes involved [1].…”

“…Molecular dynamic (MD) simulations can provide detail structural information and mechanical behaviors of nanocomposites at atomic scale and may be efficient in the design of nanocomposites Zhou et al systematically studied the effect of loading angle [11], orientation angle [12] and interfacial strength [13] on the deformation process of nanocomposites. Dangare et al [1] observed the strengthening behaviors and the tension-compression strength asymmetry of Al/Si nanocomposites with using MD simulations. It was observed that the strength of the nanocomposites increase linearly with increase of the VF of Si in the Al-rich region.…”

“…In addition, Yang et al [17] and Feng et al [18][19][20] found the VF of SiC, interfacial properties and thermo effects play important roles in the plastic deformation of the co-continuous Cu/SiC nanocomposites. Although some studies on nanocomposites had been performed by experiments [3,5,21] and simulations [1,17,22,23], the effect of the reinforcement on the deformation and failure mechanism is not clear yet.…”

Effects of interface cohesion on mechanical properties of interpenetrating phase nanocomposites

“…However, the MEAM potential has a cutoff mechanism in its many‐body angular screening function, which makes this simulation potential computationally expensive. To incorporate the angular dependence with a unified functional form, an angular‐dependent embedded atom method (A‐EAM) potential for mixed metal–covalent systems has been developed [34, 35]. This potential is formulated by combining the EAM potential for aluminium with the Stillinger‐Weber (SW) potential for silicon.…”