Phase formation during mechanical alloying in the Ti–Si system

✍ Scribed by Yoo-Sung Lee; Sung-Man Lee

• Publisher: Elsevier Science
• Year: 2007
• Tongue: English
• Weight: 267 KB
• Volume: 449-451
• Category: Article
• ISSN: 0921-5093
• DOI: 10.1016/j.msea.2006.02.247

✦ Synopsis

Mechanical alloying of Ti-Si powder mixture or TiH 1.924 -Si powder mixture was performed by high-energy ball milling, in which the Ti to Si mole ratio was 1:2. The phase formations in both mixtures during milling were investigated by X-ray diffraction. Mechanical alloying a mixture of elemental powders led to the formation of TiSi 2 equilibrium compound, while when starting from Si + TiH 1.924 , a metastable phase was formed. The metastable phase completely transforms to TiSi 2 when the mechanically alloyed powder is annealed at temperatures above 800 • C. Two different pathways of phase transitions during mechanical alloying are attributed to the existence of hydrogen atoms, i.e., when starting from Si + TiH 1.924 compared to Si + Ti, the kinetics for the formation of the TiSi 2 intermetallic compound slows down. The kinetics related to the different phase transitions depending on the starting powder mixture are discussed.