Formation of Metastable Phases and Their Stability in Mechanically Alloyed Ti-48Al-12Nb-1Cr (at) System

摘要

The reported work is on Ti-48Al-12Nb-1Cr (at%) system synthesized in a high-energy planetary ball mill with optimized milling parameters. The synthesized powders are characterized by Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), X-ray Diffraction (XRD) and Differential Thermal Analysis (DTA) in order to understand the structural and phase transformation. The results obtained from the above said studies show the particles refinement, formation of non-equilibrium structures, etc. High-energy ball milling results super saturation of Al and Nb in titanium matrix at 15hrs of milling, nanocrystalline nature at 20hrs and amorphous phase formation at 50hrs of milling. Differential Thermal Analysis (DTA) and XRD scans of MA powder thermally treated at 750°C for 1hr show the formation of TiAl and TiAl{sub}3 intermetallic compounds.