Author: Yagnesh Shadangi, Vikas Shivam, Manish Kumar Singh, Kaushik Chattopadhyay,Joysurya Basu, N.K. Mukhopadhyay
Institute: Department of Metallurgical Engineering, Indian Institute of Technology (BHU), Varanasi, 221005, Uttar Pradesh, India
In recent decades, soft and hard nanoscale structures have attracted much attention from scientists due to their unique properties and potential applications in various fields, including electronics, magnetism, and catalysis. In this paper, we consider the synthesis and characterization of a nanocomposite with a quasicrystalline matrix of Al-Cu-Fe reinforced with copper with the addition of Sn, carried out by the mechanical grinding method. The mechanical destruction process allows for a significant increase in the contact surface, which improves the physicochemical properties of the resulting material.
Quasicrystals (QCs) are a relatively new category of intermetallic substances identified as part of a family of non-periodic structures first reported by Shechtman et al. QCs are characterized by remarkable hardness, excellent wear resistance, low coefficient of friction, and a combination of low thermal and electrical conductivity with good corrosion resistance.
It is noteworthy that, in addition to the initially identified metallic QCs, liquid quasicrystals were discovered in a polymer system in 2004. Among the various metallic alloy quality control systems, Al-Cu-Fe alloys have been widely investigated due to their availability, safety, and cost effectiveness. These alloys are especially studied for their potential use in coatings, catalysis, and strengthening of aluminum-based composites. The composition range of 58-70% Al, 20-28% Cu, and 10-14% Fe provides stable formation of icosahedral quasicrystalline phase.
Mechanical milling (MM) and mechanical alloying (MA) are common methods for producing nanostructured materials, with significant research focused on the synthesis of Al-Cu-Fe QCs via MA of elemental powders. The inherent brittleness of Al-Cu-Fe QCs limits their application in structures, although impact toughness can be improved by grain refinement or addition of softer phases. The objective of this study is to investigate the effect of MM duration and Sn volume fraction on the structural evolution of the IQC phase in nanocomposites.
The alloy with the composition Al62.5Cu25Fe12.5 (in %) (called IQC) was prepared by melting in a vacuum induction furnace. Before milling, the as-prepared IQC was subjected to a homogenization process at 800 °C for 4 hours. To support this study, the matrix of IQC was reinforced with 10, 20 and 30 vol% Sn, designated as IQC-10Sn, IQC-20Sn and IQC-30Sn, respectively. The structural and microstructural changes upon MM were investigated by X-ray diffraction (XRD) [Coupled with Ka; at 40 kV/40 mA], scanning electron microscopy (SEM) [NOVA NanoSEM 450; at 30 kV] and transmission electron microscopy (TEM) [TECNAI G2 20; [at 200 kV]. The chemical composition was analyzed using SEM-EDS and STEM-EDS methods. The thermal stability of MM nanocomposite powders was evaluated using differential scanning calorimetry (DSC) in an inert N2 environment at a heating rate of 50°C/min.
Having synthesized the nanocomposite, we performed its structural analysis using X-ray diffraction, scanning electron microscopy and atomic force microscopy. The results indicate the formation of a quasi-crystalline phase with high thermodynamic stability. The addition of Sn contributed to the improvement of the mechanical characteristics of the material, which makes it promising for use as an innovative building material. Thus, we were able to demonstrate the efficiency of the synthesis and the potential for using the Al-Cu-Fe/Sn nanocomposite in modern technologies.