Navegando por Palavras-chave "Phase transitions"

Agora exibindo 1 - 5 de 5
  • Nenhuma Miniatura disponível
    Item
    Somente Metadadados
    Ag-rich precipitates formation in the Cu-11%Al-10%Mn-3%Ag alloy
    (Elsevier B.V., 2014-12-05) Silva, R. A. G. [UNIFESP]; Paganotti, A. [UNIFESP]; Jabase, L. [UNIFESP]; Adorno, A. T.; Carvalho, T. M.; Santos, C. M. A.; Universidade Federal de São Paulo (UNIFESP); UNESP
    The formation of Ag-rich precipitates in the Cu-11%Al-10%Mn-3%Ag alloy initially quenched from 1123 K was analyzed. the results showed that nanoprecipitates of a Cu-rich phase are produced at about 523 K. in higher temperatures these nanoparticles grow and the relative fraction of Ag dissolved in it is increased, thus forming the Ag-rich phase. (C) 2013 Elsevier B.V. All rights reserved.
  • Nenhuma Miniatura disponível
    Item
    Somente Metadadados
    Completeness of beta-phase decomposition reaction in Cu-Al-Ag alloys
    (Springer, 2012-08-01) Silva, R. A. G. [UNIFESP]; Machado, E. S.; Adorno, A. T.; Magdalena, A. G.; Carvalho, T. M.; Universidade Federal de São Paulo (UNIFESP); Universidade Federal de Sergipe (UFS); UNESP
    The completeness of beta-phase decomposition reaction in the Cu-11wt%Al-xwt%Ag alloys (x = 0, 1, 2, and 3) was studied using differential scanning calorimetry (DSC), X-ray diffractometry (XRD), and optical microscopy (OM). the results indicated that beta-phase transformations are highly dependent on cooling rate and on the presence of Ag. On slow cooling, the silver presence prevents the beta- and beta(1)-phase decomposition; thus, inducing the martensitic phase formation. After rapid cooling, a new thermal event is observed and the reverse martensitic transformation is shifted to lower temperatures.
  • Nenhuma Miniatura disponível
    Item
    Somente Metadadados
    Effect of Ag addition on phase transitions of the Cu-22.26 at.%Al-9.93 at.%Mn alloy
    (Elsevier B.V., 2013-02-20) Silva, R. A. G. [UNIFESP]; Gama, S. [UNIFESP]; Paganotti, A. [UNIFESP]; Adorno, A. T.; Carvalho, T. M.; Santos, C. M. A.; Universidade Federal de São Paulo (UNIFESP); Univ Estadual Paulista
    The phase transitions that occur in the Cu-22.26 at.%Al-9.93 at.%Mn and Cu-22.49 at.%Al-10.01 at.%Mn-1.53 at.%Ag alloys after slow cooling were studied using differential scanning calorimetry at different heating rates, microhardness changes with temperature, magnetization changes with temperature, scanning electron microscopy and energy dispersion X-ray spectroscopy. the results indicated that the presence of Ag does not modify the transition sequence of Cu-Al-Mn alloy, introduces a new transition due to the (Ag-Cu)-rich precipitates dissolution at about 800K, and changes the mechanism of DO3 phase dissolution. This mechanistic change was analyzed and a sequence of phase transitions was proposed for the reaction. (C) 2013 Elsevier B.V. All rights reserved.
  • Nenhuma Miniatura disponível
    Item
    Somente Metadadados
    Investigation of thermal, mechanical and magnetic behaviors of the Cu-11%Al alloy with Ag and Mn additions
    (Elsevier B.V., 2013-01-01) Silva, R. A. G. [UNIFESP]; Paganotti, A. [UNIFESP]; Gama, S. [UNIFESP]; Adorno, A. T.; Carvalho, T. M.; Santos, C. M. A.; Universidade Federal de São Paulo (UNIFESP); UNESP
    The investigation of thermal, mechanical and magnetic behaviors of the Cu-11%Al, Cu-11%Al-3%Ag, Cu-11%Al-10%Mn and Cu-11%Al-10%Mn-3%Ag alloys was made using microhardness measurements, differential scanning calorimetry, X-ray diffractometry, scanning electron microscopy, energy dispersion X-ray spectroscopy and magnetic moment change with applied field measurement. the results indicated that the Mn addition changes the phase stability range, the microhardness values and makes undetectable the eutectoid reaction in annealed Cu-11%Al and Cu-11%Al-3%Ag alloys while the presence of Ag does not modify the phase transformation sequence neither microhardness values of the annealed Cu-11%Al and Cu-11%Al-10%Mn alloys, but it increases the magnetic moment of this latter at about 2.7 times and decreases the rates of eutectoid and peritectoid reactions of the former. (C) 2012 Elsevier Inc. All rights reserved.
  • Nenhuma Miniatura disponível
    Item
    Somente Metadadados
    Thermomagnetic behavior of an as-quenched Cu-Al-Mn-Gd alloy
    (Elsevier Science Sa, 2018) Oliveira, A. B. [UNIFESP]; Silva, R. A. G. [UNIFESP]
    The thermomagnetic behavior of the as-quenched Cu-9wt%Al-10 wt%Mn-3wt%Gd alloy was studied using differential scanning calorimetry (DSC), optical microscopy, magnetization measurements with temperature and applied field. The results obtained showed that in the Cu-9wt%Al alloy the alpha, gamma(1) and alpha(2) phases are produced from martensitic beta' phase decomposition while in the Cu-9wt%Al-3wt%Gd alloy the higher fraction of produced gamma(1) phase is not formed from martensite decomposition. In the Cu-9wt%Al-10 wt%Mn and Cu-9wt%Al-10 wt%Mn-3wt%Gd alloys the ferromagnetic Cu2AlMn phase formation is dependent on the cooling rate and the martensitic transition seems to be changed by the presence of Gd. (C) 2018 Elsevier B.V. All rights reserved.