Reyes Russi, Luvina

Profile Picture

Filters

20071
Reset filters

Settings

Citations

Publication Search Results

Now showing 1 - 1 of 1
  • Thumbnail Image
    Publication
    Synthesis and characterization of (AlMg)B2- aluminum based composites and nanocomposites
    (2007) Reyes Russi, Luvina; Suárez, O. Marcelo; College of Engineering; Sundaram, Paul A.; Pérez, Nestor J.; Department of Mechanical Engineering; Santos Cordero, Jeannette
    The present study involves a novel method to synthesize under vacuum (AlMg)B2 – aluminum based composites. Incorporation of MgB2 into aluminum is a complex process because of the lack of wettability between both components. Aluminum high surface tension and oxide layer (Al2O3) formation most likely prevent magnesium diboride from mixing with liquid aluminum. High energy ball milling was selected as a key process to achieve appropriate mixing and wettability between alloy components. Many runs were completed to study processing variables such as rpm and milling time variables among others prior to get the appropriate parameters that lead to the desired mechanical mixing. Two target compositions of Al pellets (840-2400μm) and MgB2 powder (5wt%- 10wt% / 44μm) were selected at the beginning of the experimentations. A hydraulic press was used to consolidate and compact the composite after mechanical alloying for further melting reaction (in conventional furnace) of the samples placed into evacuated quartz tubes and sealed. A good incorporation of aluminum matrix with MgB2 produced discontinuous intermetalics particles and nanoparticles of (AlMg)B2 into the aluminum matrix where eutectic Al3Mg2 is also present. Microstructural characterization of composite samples revealed a 2% increase in the reinforcement volume fraction Al-10wt%MgB2 compared with the other composition at 5wt%MgB2. Bigger particle sizes are present in the samples containing Al-5wt%MgB2 but this composition also L. Reyes-Russi, Master Thesis, UPRM-RUM 2007 III presented the highest content of nanometer sized particle reinforcement leading to the highest values of Vickers microhardness. Furthermore, SEM-EDS analysis helped to confirm that the ballmilling process promoted nanosized particles of (AlMg)B2 composite. XRD test showed peaks associated to (AlMg)B2 along with Al, AlB2, and MgB2 between 20° y 45°. Also this spectrum reveals the formation of Al3Mg2 phase, and corroborated in the micrographs. DTA curves obtained showed a dome at 820o C in the exothermic reaction associated with the dissolution of the ternary phase (AlMg)B2. Using CARIne® v3.1 software, a crystallographic modeling of (AlMg)B2 phase is presented at the end of the research. As an attempt to quantify the presence of this ternary phase in the composite alloys, the XRD diffractograms of the samples were used as the starting point for the modeling analysis were a resulting stoichiometric composition of the final model is approximately (Al0.5Mg0.5)B2.