摘要
研究了Cu72Al26.5Nb1.5高温记忆合金马微观组织结构与马氏体相变行为。结果表明,Cu72Al26.5Nb1.5合金的铸态显微组织由基体相、γ2相、Nb(Cu、Al)以及Nb(Cu、Al)2相组成,冷却速度越快,γ2相越少;而Nb(Cu、Al)与Nb(Cu、Al)2相并未随冷却速度变化而发生明显改变。Cu72Al26.5Nb1.5合金在加热冷却过程中发生β1→β1马氏体正逆相变。母相为D03有序的BCC结构,马氏体为M18R堆垛有序单斜结构,马氏体变体多呈自协作形态,变体内部亚结构主要为(1210)孪晶。时效对试验合金相变温度影响较大,在马氏体状态下时效,呈现出较强的马氏体稳定化现象,逆相变温度随时效时间的延长而显著升高。在母相状态下时效,马氏体相变温度随时效时间的延长先下降后上升,最后趋于稳定;在时效初期,逆相变温度随时效时间的延长而增大,在时效后期,逆相变温度随时效时间延长基本不发生变化。
Microstructure and martensitic transformation behavior of the Cu72Al26.5Nb1.5 high temperature shape memory alloy have been studied. The experimental results show that the microstructure of the as-melted Cu72Al26.5Nb1.5 alloy consists of four phases： matrix, phase, Nb（Cu, Al） phase and Nb（Cu, Al）2 phase. With the increase of cooling rate, the amount of the γ2 phase decreases, while the shape and amount of the Nb（Cu, Al） phase and Nb（Cu, Al）2 phase have no obvious change,β1＇←→β1 martensitic transformation/reverse transformation occurs during cooling/heating. The parent phase has a D03-0rdered BCC structure while the martensite has a M18R monoclinic structure. The martensite of the experimental alloy mainly exhibits self-accommodation morphology, and the substructure is mainly （1210） twin. The alloy aged in the martensite shows the pronounced martensite stabilization, i.e. reverse transformation temperatures increase remarkably with the increase of aging time. When aging in the parent phase, martensitic transformation temperatures drop at the first stage, then increase with the increase of aging time. With further aging, the transformation temperature shows stable value. The reverse transformation temperature increases at the early stage of aging and keeps constant with the further increase of aging time.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2008年第9期1560-1565,共6页
Rare Metal Materials and Engineering
