系统研究了CuZnAlMnNi记忆合金在低温下的相变特性,发现该合金淬火到马氏体态后,在继续冷却过程中,接着发生马氏体组织(M)向X-相的转变;在随后的加热过程中首先发生X→M转变,然后发生马氏体逆转变。把这两个在较低温度下相继发生的相变定义为CuZnAlMnNi合盒中的双可逆相变。X-相与马氏体组织具有相似的晶体结构,使X→M转变的相变焓远小于马氏体逆转变的相变焓。热循环使X→M转变温度降低,导致两个相变峰发生分离,但相变焓却基本保持不变。快速加热对X→M转变具有一定的抑制作用,随着加热速率减小,两个相变峰逐渐发生分离。不同成分的合金两个相变峰发生分离的加热速率不同。母相时效使转变温度和相变焓均发生了一定程度的波动,而且对X→M转变的影响大于对马氏体逆转变的影响。马氏体态时效有利于X→M转变的进行,使其转变温度升高,参与转变的组织量增多。发生双可逆相变后,形成的X-相穿越马氏体组织,使马氏体板条中的层错亚结构变得混乱,合金的有序度降低,致使合金的记忆性能降低。合金在淬火过程中,初始形成的细小马氏体板条中存在着一系列整齐排列的位错环。随着马氏体板条长大,位错不沿着长度或宽度方向扩展,形成与板条边界成一定角度的或与板条边界大致平行的堆垛层错。位错环对马氏体板条的长大产生一定的阻碍作用,如果板条长大的驱动力难以克服位错环的阻碍作用,板条即停止长大,使细小板条中的位错环即使在室温下也依然可见;否则,马氏体板条将一直长大到相互接触,位错环可以进行充分的扩展,演化成在淬火马氏体组织中最常见的堆垛层错亚结构。合金经离子减薄后,在室温长期放置过程中发生氧化,沿着层错面、在位错线周围、在层错四面体处或沿马氏体板条边界形成氧化物颗粒,使合金中的层错亚结构减少,局部区域甚至完全消失,导致合金记忆性能降低。 The phase transition behavior of CuZnAlMnNi memory alloy at low temperature was systematically studied. It was found that the transformation of martensite (M) to X-phase followed by cooling after the alloy was quenched to martensite. During the subsequent heating X → M transformation occurs first in the process, and then martensitic transformation occurs. The two successive phase transitions at lower temperatures are defined as the dual reversible phase transitions in the CuZnAlMnNi junction box. The X-phase and martensite have a similar crystal structure, so that the enthalpy of phase transition of X → M transformation is much smaller than the enthalpy of phase transformation of martensitic transformation. Thermal cycling reduces the transition temperature of X → M, resulting in the separation of the two phase transition peaks, but the phase transition enthalpy remains essentially unchanged. Rapid heating of X → M transition has a certain inhibitory effect, with the heating rate decreases, the two phase transition peaks gradually separated. Different compositions of the alloy two phase transition peak separation heating rate is different. The aging of the mother phase caused a certain degree of fluctuation in both the transformation temperature and the enthalpy of phase transformation, and the influence on the X → M transformation was greater than that on the martensitic transformation. Martensite aging is conducive to the X → M transition to make its transition temperature increased, the amount of tissue involved in the transformation increased. After the dual reversible phase change, the X-phase formed through the martensite, the lamellar sub-structure of martensite lath disorder, chaussures louboutin, the degree of order of the alloy decreases, resulting in reduced memory properties of the alloy. During the quenching process, a series of neatly arranged dislocation loops exist in the initially formed fine martensite laths. As the martensite lath grows, the dislocations do not expand in length or width, creating a stacking fault that is at an angle to the lath boundary or generally parallel to the lath boundary. Dislocation loops may hinder the growth of martensite lath. If the driving force of lath growth is hard to overcome the obstruction of the dislocation loop, the lath will stop growing and dislocations in the lamella The rings are still visible even at room temperature; otherwise, the martensite laths will grow up into contact with each other, the dislocation loops may expand sufficiently to evolve into the most common stacking fault in quenched martensite structure. The alloy is ionized and thinned and oxidized during long-term placement at room temperature. Oxide particles are formed along the stacking fault surface, around the dislocation line, at the stacking fault tetrahedrons or along the martensite slab boundary, Of the layers of the fault sub-structure to reduce the local area or even completely disappear, resulting in reduced memory alloy performance.