Study of Ti-7.5Si-22.5B alloys produced by powder metallurgy

• Autor(a) principal: Fernandes,Bruno Bacci
• Data de Publicação: 2014
• Outros Autores: Moura Neto,Carlos de, Ramos,Alfeu Saraiva, Melo,Francisco Cristóvão Lourenço de, Henriques,Vinícius André Rodrigues
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Materials research (São Carlos. Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392014000300004
• topic: powder metallurgy; titanium alloys; vickers hardness

Refractory alloys with silicides and borides have been used in high temperature applications because their elevated melting point, good oxidation resistance and high strength-to-weight ratio. The present study approaches the preparation of Ti-7.5Si-22.5B (at.-%) alloys through high-energy ball milling and sintering. The powders and compacts obtained in these processes were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), density measurements, chemical analyses and Vickers hardness. It was verified that silicon and boron powders are dissolved in the titanium during milling with an iron contamination up to 6.0 at.-%. Furthermore, the use of short milling times and alcohol during the final stages of milling increases the powder yield. Such increasing was obtained even with a high rotary speed (300 rpm), which generally creates higher temperatures and consequently more sticking. After sintering of the as-milled powders, it was indentified mainly the Ti+Ti6Si2B+TiB+Ti5Si3 phases in the Ti-7.5Si-22.5B sintered alloys, which presented hardness values up to 800 HV. The materials produced by the present work can be employed in coating research as sputtering targets.