Cyclic Nano-Indentation study of Sintered Aluminium and Aluminium-Copper Alloy Reinforced (Cu66Zr34) Metallic Glass Composites: A Molecular Dynamics Study

Abstract

Molecular dynamics (MD) simulations are carried out for cyclic nano-indentation on sintered metal (Al)-metallic glass (Cu66Zr34) reinforced composites termed as composite-I and on sintered alloy(Al-4%Cu)-metallic glass (Cu66Zr34)termed as composite-II to measure the hardness, stiffness and reduced young modulus.I ndenter radius, and indentation speed effects on the load-displacement behavior, hardness, stiffness, and young modulus has been studied. Depth-sensing cycling nano-indentation is studied to assess depth-dependent plastic deformation of the composite at room temperature. The results showed that the plastic deformation continued to take place and the continuous displacement increased as the number of indentation increased. We have found that composite-II sample shows high mechanical properties like hardness, stiffness and reduced young modulus than composite-I.But, there was reduction in the plasticity of the composite-II to enhance other mechanical properties such as Hardness and stiffness.Furthermore, the initial hardness is seen to slightly increase with increase in indenter radius, indentation speed and alloying element. After each cyclic nano-indentation, the loading curve overlapped with the previous unloading curve and had a small displacement after each reloading cycle.
From the first loading-unloading cycle, plastic deformation continued to take place and the continuous displacement increased as the number of indentations increased. The stiffness was seen to remain constant for a constant cycle and increased with increase in number of cycles and was seen to remain constant after few cycles.