| The resistance to high-temperature aging and the resistance to thermal cycling fatigue of Cu-24Al-3Mn-2Ti (atomic fraction,%)alloy and Cu-23Al-2Mn-3Ti-2Zn (atomic fraction,%) alloy have been studied in this paper.At the same time,the microstructure, substructure and crystal structure in Cu-24Al-3Mn-2Ti (atomic fraction,%)alloy and Cu-23Al-2Mn-3Ti-2Zn (atomic fraction,%) alloy are studied by means of SEM observation,TEM observation and X-ray diffraction and so on.It is shown that the aging treatment and the thermal cycling can have influences in the shape memory effect.The shape recovery ratio increases and then decreases orderly together with the aging time's prolonging and aging temperature's improving.The shape memory effect of Cu-24Al-3Mn-2Ti (atomic fraction,%)alloy is the best when in aging treatment at 400℃with a shape recovery ratio higher than 94.8%.The increasing times of thermal cycling can decline the shape recovery ratio.The shape memory effect can keep being higher than 91.43% when Cu-24Al-3Mn-2Ti (atomic fraction,%)alloy is treated in thermal cycling between room temperature and 400℃for 200times.It is known the Cu-24Al-3Mn-2Ti (atomic fraction,%)alloy has the resistance of high temperature.Having been solutionizing at 900℃and water quenching at room temperature,this paper can now conform that the basic body of the quenching alloy exhibiting lath-shaped martensite is body-centered cubic AlCu3, with lots of grey precipitated phase AlCu2Ti distributing on basic body and grain boundary and few fine silvery white solid solution phase of Cu-Zn.By carrying out of the aging treatment and thermal cycaling,the martensite will be stabilized and take place eutectoia reaction. white reticulationα-phase which tend to be found on grain boundary andγ-phase which is electron compound Cu9Al4 appear,leading to the martensite phase closeing to the precipitate phase turn to the needle-like twin martensite.At the same time,the microstructure turns to be rougher and biger.Tt is known that the quenching martensite of Cu-24Al-3Mn-2Ti (atomic fraction,%)alloy and Cu-23Al-2Mn-3Ti-2Zn (atomic fraction,%) alloy which having been solutionizing at 900℃and water quenching at room temperature are mainly fault which can be signed M18R.After aging treatment at 500℃for 30 minutes,the substructure is fault and twin which can be signed 2H.In addition,lots of different shaped dislocation come out in basic body especially around the precipitate phases.The Cu-based shape memory alloy has high resistance to high-temperature aging,stabilization of martenmasite and thermal cycling fatigue which can apply to high temperature circumstance instead of some shape memory alloy.The alloy studied in this article expend the apply range of Cu-based shape memory alloy.
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