Structural Evolution of Ti-Fe-Si-B Alloys Produced by High-Energy Ball Milling and Sintering

Abstract

This proposal aims at structural characterization of Ti-Fe-Si-B alloys produced by high-energy ball milling and subsequent sintering. In this study, quaternary alloys were prepared from raw materials of high purity: Ti (99.9 wt-%), Fe (99.8 wt-%), Si (99.999 wt-%) and B (99.5 wt-%). The milling process of the Ti-2Fe-22Si-11B and Ti-7Fe-22Si-11B (at-%) powders was carried out in a planetary Fritsch P-5 ball mill. Subsequently, the Ti-Fe-Si-B powders milled for 600 min were sintered (1100 ° C for 240 min) under vacuum to obtain equilibrium structures. The characterization of as-milled powders and sintered alloys was performed by means of X-ray diffraction, scanning electron microscopy, and electron dispersive spectrometry. Extended solid solutions were formed during the initial milling times while that the brittle Ti5Si3 phase was formed for longer milling times in both the quaternary powder mixtures. This fact contributed for reducing the particle sizes. Homogeneous samples containing a small amount of pore were obtained after sintering at 1100°C for 4h. Results have indicated that the iron addition favored the formation of different binary phases of the Ti-Si system, and the formation of the Ti6Si2B compound was inhibited from the Ti-Fe-Si-B powder mixtures.