Phase transformations of Ni-15 wt.% B powders during mechanical alloying and annealing

The formation of Ni–B binary intermetallic compounds was investigated by mechanical alloying (MA) of the Ni-15 wt.% B (≈ Ni-48 at.% B) powder mixture and subsequent heat treatment. It was found that an interstitial Ni(B) solid solution was formed at the early stage of milling, followed by the formation of Ni3B intermetallic compound after 25 h of milling. On further milling, the Ni3B transformed to Ni2B and o-Ni4B3 (orthorhombic). Phase transformation during heating of Ni(B) solid solution phase up to 800 °C could be represented by Ni(B) → Ni3B → Ni2B. Other intermetallics can be formed by heat treatment of Ni(B) solid solution at temperatures above 800 °C.