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根据有序化理论 ,提出了预时效概念 ,并用无析出物形成的预时效处理研究了Cu - 13.4Al - 4.0Ni单晶相变温度随预时效工艺的变化 ,结合DSC和偏光金相分析探讨了预时效与时效的界限 .淬冷状态的Cu-Al-Ni单晶其相变温度可以根据需要进行预时效处理 ,经预时效后 ,其Ms为淬冷态的Ms +0～ 70℃ ,As为淬冷态的 As+0～ 90℃可调 .预时效温度应为淬冷态的 Ms+10 0～ 2 0 0℃ .经过预时效的合金在马氏体状态下其相变温度保持稳定 .在高出淬冷态合金Ms点 30 0℃以上随着保温温度的升高或保温时间的增长 ,处理后的Ms、As等转变温度向高温移动 ,并且相应的 β′1相的数量也会降低 ,γ′1相量增加 .尽管此时没有析出物产生 ,但是单一 β′1相转变为 β′1+γ′1后 ,由于γ′1相很差的原位再现性而导致降低形状记忆行为和超弹行为 .
Based on the theory of ordering, the concept of pre - aging is proposed and the change of the transition temperature of Cu - 13.4Al - 4.0Ni single crystal with the pre - aging process is studied by the pre - aging treatment without any precipitate formation. Combined with DSC and polarized light phase analysis The pre-aging and aging limits.Quenching Cu-Al-Ni single crystal its phase transition temperature can be pre-aging treatment as needed, after pre-aging, the Ms is quenched Ms + 0 ~ 70 ℃, As is quenched As + adjustable from 0 to 90 ° C. The pre-aging temperature should be quenched Ms + 10 0 ~ 200 ° C. After the pre-aging of the alloy in the martensite phase transition temperature is maintained Above the quenched alloy Ms point above 30 0 ℃ with the holding temperature or holding time increases, the treated Ms, As and other transition temperature to high temperature, and the corresponding number of β’1 phase Will decrease, and the γ’1 phasic increase.Although no precipitates were formed at this time, the single β’1 phase was transformed to β’1 + γ’1 due to poor in-situ reproducibility of γ’1 phase Decrease shape memory behavior and superelastic behavior.