Navegando por Palavras-chave "mechanical alloying"

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    The formation of quasicrystal phase in Al-Cu-Fe system by mechanical alloying
    (ABM, ABC, ABPol, 2012-10-01) Travessa, Dilermando Nagle [UNIFESP]; Cardoso, Kátia Regina [UNIFESP]; Wolf, Witor; Jorge Junior, Alberto Moreira; Botta, Walter José; Universidade Federal de São Paulo (UNIFESP); Universidade Federal de São Carlos Departamento de Engenharia de Materiais
    In order to obtain quasicrystalline (QC) phase by mechanical alloying (MA) in the Al-Cu-Fe system, mixtures of elementary Al, Cu and Fe in the proportion of 65-20-15 (at. %) were produced by high energy ball milling (HEBM). A very high energy type mill (spex) and short milling times (up to 5 hours) were employed. The resulting powders were characterized by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). QC phase was not directly formed by milling under the conditions employed in this work. However, phase transformations identified by DSC analysis reveals that annealing after HEBM possibly results in the formation of the ψ QC phase.
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    Preparation and characterization of stainless steel 316L/HA biocomposite
    (ABM, ABC, ABPol, 2013-04-01) Silva, Gilbert; Baldissera, Márcia Regina; Trichês, Eliandra de Sousa [UNIFESP]; Cardoso, Kátia Regina [UNIFESP]; Universidade Federal de Itajubá IEM; Universidade Federal de Itajubá Instituto de Ciências Exatas; Universidade Federal de São Paulo (UNIFESP)
    The austenitic stainless steel 316L is the most used metallic biomaterials in orthopedics applications, especially in the manufacture of articulated prostheses and as structural elements in fracture fixation, since it has high mechanical strength. However, because it is biologically inactive, it does not form chemical bond with bone tissue, it is fixed only by morphology. The development of biocomposites of stainless steel with a bioactive material, such as hydroxyapatite - HA, is presented as an alternative to improve the response in the tissue-implant interface. However significant reductions in mechanical properties of the biocomposite can occur. Different compositions of the biocomposite stainless steel 316L/HA (5, 20 and 50 wt. (%) HA) were prepared by mechanical alloying. After milling the powders for 10 hours, the different compositions of the biocomposite were compacted isostatically and sintered at 1200 ºC for 2 hours. The mechanical properties of the biocomposites were analyzed by compression tests. The powders and the sintered composites were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD).