The mechanical alloying process has been recognized as a novel technique in synthesizing stable and metastable alloys through solid-state reaction without involving melting. However, many invstigators are well aware that the mil領(lǐng) time necessary to complete the formation of metastable phases is strongly dependent on the mil領(lǐng) conditions such as the type of mill, the size and number of balls and the motion of the balls. For instance, mechanical alloying experiments have been extensively carried out on the Ni-Zr alloy system. The mil領(lǐng) time for the completion of the amorphization for Ni:Zr--1:1 powders is distributed over 20-400 h [1-5]. This clearly indicates that the mil領(lǐng) conditions affect very sensitively the mil領(lǐng) time to produce a final product. 行星式高能球磨儀