Analysis of contamination in the process of forming a titanium-based nanocrystalline alloy using VSM, SEM-EDS, and XRD techniques

Abstract

In this study, nanocrystalline TiAlV alloys were synthesized using the mechanical alloying technique with a high-energy planetary ball mill from pure Ti, Al, and V powders. Various methods, including Vibrating Sample Magnetometry (VSM), Scanning Electron Microscopy and Energy Dispersive Spectroscopy (SEM-EDS), and X-ray Diffraction (XRD), were employed to characterize the synthesized alloys and study their magnetic behavior, morphology, microstructural and structural properties, respectively. Following the XRD analysis, new phases were confirmed, and a significant reduction in crystallite size from 48.73 to 9.38 nm was observed. Moreover, an increase in lattice strain from 0.15% to approximately 0.81% was noted after 60 h of milling. The EDS analysis gave remarkable results, showing the lack of magnetic iron particles before milling. However, after milling, the EDS spectrum revealed the presence of these magnetic iron particles with varying concentrations. This important observation highlights the profound impact of the mechanical alloying process on the sample composition. It emphasizes the sensitivity of EDS analysis by detecting even subtle changes in the elementary composition of a material. A sensitive approach was employed to monitor the progression of the nanocrystalline alloy and identify any potential defects arising during the mechanical milling. A vibrating sample magnetometer was utilized to achieve this objective. This method is highly effective at capturing even subtle changes that may occur during milling, allowing for an accurate evaluation of the chemical composition and integrity of the alloy. This technique made it possible to detect the presence of magnetic particles whose magnetic properties varied from time to time, indicating a change in magnetic behavior due to the reduction in the size of these particles caused by the collision between the steel balls and the milled powder particles. The results suggest that non-destructive magnetic testing using a VSM can be used to monitor the state of the nanocrystalline alloy.