On the Phase Transformation in Mechanically Alloyed Ni-Nb and Ni-Ta and Ni-Nb-Ta Powders

• Autor(a) principal: Ferraretto, Ana Clara [UNESP]
• Data de Publicação: 2012
• Outros Autores: Trindade Ramos, Erika Coaglia, Ramos, Alfeu Saraiva [UNESP]
• Tipo de documento: Artigo de conferência
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.4028/www.scientific.net/MSF.727-728.222; http://hdl.handle.net/11449/9382
• topic: nickel alloys; mechanical alloying; metastable structures

This paper reports on the phase transformation during the preparation of Ni-25Nb, Ni-25Ta, Ni-20Nb-5Ta and Ni-15Nb-10Ta (at-%) powders by high-energy ball milling from elemental powders. The milling process was performed in a planetary ball milling using stainless steel balls and vials, rotary speed of 300rpm, and a ball-to-powder of 10:1. To minimize contamination and spontaneous ignition the powders were handled under argon atmosphere in a glove box. The milled powders were characterized by means of X-ray diffraction techniques. Results indicated that the Ni atoms were preferentially dissolved into the Nb (and/or Ta) lattice at the initial milling times, which contributed to change the relative intensity on the diffraction peaks. After the dissolution of Nb (and/or Ta) into the Ni lattice, the Ni peaks were moved to the direction of lower diffraction angles in Ni-25Nb, Ni-25Ta, Ni-20Nb-5Ta, Ni-15Nb-10Ta powders, indicating that the mechanical alloying was achieved.