The Al6Li3Cu (T2) phase, which exhibits five-fold or icosahedral symmetry, forms through solid state precipitation in dilute Al-Li-Cu alloys. Recent studies have reported that the T2 phase transforms either during TEM examination of thin foils or following ion-milling of thin foil specimens. Related studies have shown that T2 phase transforms to a microcrystalline array of the TB phase and a dilute aluminum solid solution during in-situ heating in the TEM. The purpose of this paper is to report results from an investigation of the influence of ion-milling on the stability of the T2 phase in dilute Al-Li-Cu alloy.The 3-mm diameter TEM disc specimens were prepared from a specially melted Al-2.5%Li-2.5%Cu alloy produced by conventional procedures. The TEM specimens were solution heat treated 1 h at 550°C and aged 1000 h at 190°C in air to develop the microstructure. The disc specimens were electropolished to achieve electron transparency using a 20:80 (vol. percent) nitric acid: methanol solution at -60°C.
In situ NbC and VC nanoparticles reinforced Fe-Si-Mn-Nb-V matrix composite was carried out using a plasma jet with a plasma gas flow of (Ar + CH4) for very short time. The process involve improving the efficiency of the reaction in terms of consumption of the available active nitrogen atoms as well as the production of very fine and homogeneous distribution of all reinforcing phases of ceramic particles, preferable in the nanometer range. The nanoreinforcements synthesized by in situ reaction in this hybrid composite are NbC and VC ceramic particles.
Numerical study of thermo-hydro-mechanical responses of in situ heating test with phase-field model