Evolution of the Composition and Morphology of Ti–18 Zr–15 Nb Alloy Powder during Calcium Hydride Synthesis

Influence of temperature and duration of calcium hydride synthesis on the phase composition and morphological characteristics of Ti–18Zr–15Nb (at %) alloy powder was studied. It has been shown that, with increasing duration and temperature of synthesis, the average size of powder particles increases and the nature of particle size distribution changes owing to the formation of agglomerates. When a β-solid solution is formed, the synthesis process develops in three stages. The first stage is controlled by reduction reactions at the oxide–liquid calcium contact surface. The third stage is controlled by heterodiffusion in the solid solution. At the second stage, the synthesis process combines both mechanisms.