| Summary: | 碩士 === 國立海洋大學 === 材料工程研究所 === 88 === This study examined the amorphization behavior of Ti94-x-yCuxNiySi4B2 alloy powders synthesized by mechanical alloying technique. According to the results, after 5~7 hours of milling, the mechanically alloyed powders were amorphous at compositions with (x+y) equal to 20~40%. For the compositions with (x+y) larger than 45% or smaller than 10%, the structure of ball-milled powders is either a partial amorphous single phase or coexistent partial amorphous and crystalline phases. The thermal stability of the amorphous powders was also investigated by differential thermal analysis. As the results demonstrated, several amorphous powders were found to exhibit a wide supercooled liquid region before crystallization. The temperature interval of the supercooled liquid region defined by the difference between Tg and Tx, i.e.ΔT=Tx-Tg), is 82K for Ti74Ni20Si4B2, 94K for Ti64Ni30Si4B2, 58K for Ti64Cu10Ni10Si4B2, 116K for Ti54Cu10Ni30Si4B2, 131K for Ti54Cu20Ni20Si4B2,and 94K for Ti54Cu30Ni10Si4B2. The glass transition process in the Ti64Ni30Si4B2 is found to be a kinetically modified thermodynamics phase transformation process.
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