THERMAL STABILITY OF NANOSTRUCTURED Al-11.6Fe-1.3V-2.3Si ALLOY PRODUCED BY MECHANICAL ALLOYING AND HOT PRESSING METHODS

Thermal stability of nanostructured Al-11.6Fe-1.3V-2.3Si (wt.%) alloy was investigated. In this regard, the nanostructured Al-11.6Fe-1.3V-2.3Si alloy first produced by mechanical alloying (MA) and subsequent hot pressing (HP) of elemental powders. Structural evolution during the MA and HP were studied by X-ray diffraction (XRD). The density of hot pressed sample measured by Archimedes method. Hardness test was conducted by Vickers method at a load of 10 kg. In order to assess the thermal stability of produced alloy, hardness samples were annealed in air in a conventional furnace up to 100 h at 400°C, 500°C and 600°C. XRD results demonstrated that MA of elemental powders up to 60 h led to the formation of a nanostructured Al based solid solution. After HP, Al12(Fe,V)3Si phase precipitated in nanostructured Al matrix. Density measurement showed that the produced alloy had a relative density of ~97%. This alloy exhibit a high hardness value of 254 HV which remainsunchanged after 100 h exposure to 400°C, but decreased after annealing at 500°C and 600°C. Al12(Fe,V)3Si phase also remained stable in the Al matrix after 100 h annealing at 600°C.

Keywords:

mechanical alloying , hot pressing , thermal stability