Qingfu CHEN
,
Liancheng ZHAO
,
R.Stalmans
,
J. Van Humbeeck
材料科学技术（英文）
The superelastic behaviors of different isothermal treated Cu-13.SAl-4.ONi (mass fraction) single crystals were studied by applying tensile stress along <001> of the β phase. The different isothermal specimens have different superelastic behavior due to the change of the ratio of stress-induced γ1’and β’. The superelasticity ofγ1 phase tends to that of g, phase with cycling. Typical stabilization of stress-induced martensite above Ap results in residual deformation. Due to the reverse transformation of γ1’, there is a deviation of pseudo-yield stress form linear relation with temperature at relatively low stress.
关键词:
Qingfu CHEN
,
Wei CAI
,
Liancheng ZHAO
材料科学技术（英文）
The paper studied the relationship between microstructure and shape recovery characteristics by using colored microstructure analysis under polarized light on the thermomechanical cycled CuAINi single crystals. The two-way shape memory effect in quenched thin bar resulted from the preferential formation/extinction of martensite variant due to the internal quench stress, and the variant was formed at an angle of about 45 deg. with the tension direction ([001] of the beta phase). Initial thermomechanical cycling under relatively low stress single variant stress-induced martensite was formed at an angle of 45 deg. with the tension and its morphology was a lath of parallel twins. More than one group of variants were formed after several training cycles and such variants also caused tilting of some thermally formed accommodated martensite. By overheating the trained sample containing stabilized multi-variants of stress-induced martensite, very coarse martensite structure with a strong asymmetry was produced, which caused the reverse two-way shape memory effect.
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