Calculo termodinamico do sistema Fe-Nb e estudo experimental do sistema Fe-Ta

AUTOR(ES)

Gilberto Carvalho Coelho

DATA DE PUBLICAÇÃO

1992

RESUMO

Thermodynamic calculation of phase diagrams is a modem tool for optimization of phase diagrams, by adjusting the phase descrlbing function to experimental data. In this work, the Fe-Nb phase diagram has been calculated using two treatments. In the first one, the intermediate phases Fe2Nb and FeNb have been described as stoichiometric compounds, and, in the second, as compounds with solid solubility, using the sublattice model. The resulting phase diagrams are in good agreement with the literature data, and the phase diagram arising from the sccond treatment reproduces the peritectic reaction for the formation of the FeNb phase. which was recently verified in our laboratory. The experimental study of the Fe- Ta system has been carried out by means of t.hc following techniques: met.allography, X-ray diffractometry and electron microanalysis. Diffusion couples and samples with 20, 30, 33, 40, 42, 45, 50, 5] 60, 70 and 80%atTa have been made. A preliminary Fe- Ta phase diagram is proposed, in which the FeTa phase forms peritecticaly, and the composition ranges of the intermediate phases Fe2 Ta and FeTa aL 1400"C, have been determined as 28 to 38%at Ta and 49 to 58%atTa, respectively

ASSUNTO(S)

engenharia mecanica diagrama de fase materiais

Documentos Relacionados

• Estudo experimental do sistema Ta-Ge e da região rica em Ta do ternário Ta-Ge-B
• Crystal chemistry and structure of the orthorhombic (Fe,Mn)(Ta,Nb)2O6 family of compounds
• Microestrutura de solidificação e propriedades de ligas euteticas no sistema Fe-Al-Nb
• Obtenção e caracterização de materiais compostos In Situ no sistema Fe-Al-Nb
• Estudo da síntese e sinterização de pós compósitos do sistema Ta-Cu