预退火时间对Pd40Cu30Ni10P20玻璃转变及晶化的影响

采用示差扫描量热(DSC)分析方法,测定了大块非晶合金Pd40Cu30Ni10P20经523 K((Tg-100 K)＜7＜Tg)不同时间(0～64 h)预退火后的玻璃转变温度7g、玻璃转变峰温度TM、起始晶化温度Tx、晶化峰的峰温Tp、晶化焓以及在玻璃转变过程中的比热容增量,并根据Kissinger公式计算了晶化的表观活化能.同时,测量了不同时间预退火后样品的显微硬度.结果表明:在玻璃转变温度以下的预退火处理使Pd40Cu30Ni10P20大块非晶合金的微观原子组态发生变化,从而影响了其随后的玻璃转变行为,但对晶化的影响不大.其显微硬度随预退火时间的延长而逐步增加后趋于稳定.并利用结构弛豫理论分析了预退火对玻璃转变、晶化和显微硬度的影响.

Effect of pre-annealing time on glass transition and crystallization of Pd40 Cu30 Ni10 P20

Differential scanning calorimeter(DSC) was used to investigate the specific heat difference, glass transition temperature, onset crystallization temperature, and their corresponding peak temperature, respectively, around glass transition region and crystallization enthalpy for Pd_(40)Cu_(30)Ni_(10)P_(20) bulk amorphous alloys pre-annealed at 523 K for different times (064 h). The apparent activation energies for crystallization were calculated by Kissinger equation. The micro-hardness of pre-annealed amorphous state was also measured. It is found that the glass transition behavior of Pd_(40)Cu_(30)Ni_(10)P_(20) bulk amorphous alloy is influenced significantly due to atomic coorperation re-(arrangement) as a result of pre-annealing below glass transition temperature. The crystallization, however, seems to have no relation to pre-annealing time when pre-annealing temperature is 523 K. In addition, the micro-hardness tends to level off after a steady rise with increasing of pre-annealing time. The effects of pre-annealing time on glass transition, crystallization and micro-hardness of Pd_(40)Cu_(30)Ni_(10)P_(20) bulk amorphous alloy were discussed in terms of theory of structural relaxation.