PREPARATION AND PROPERTIES OF NANOCRYSTALLINE Ti_(70)Ni_(20)Si_(10) ALLOY

Nanocrystalline Ti70ONi20Si10 alloys with average grain sizes in the range of 8─120 nm are prepared by crystallization from amorphous precursor under isothermal heat treatment for 1h in the temperature interval of 500-800℃. X-ray diffraction and TEM analysis indicated that nanocrystalline Ti70Ni20Si10 alloy consists of three phases, i.e., Ti2Ni, Ti5Si3 and α-Ti. The values of Vickers hardness of the nanocrystalline alloy are higher than that of amorphous and as-cast samples, which does not increase linearly with reducing the grain size.