J Mater Sci Technol ›› 2001, Vol. 17 ›› Issue (05): 485-489.

• Research Articles •     Next Articles

Relationship between colored microstructure under polarized light and shape recovery characteristics on the thermomechanical cycled CuAlNi single crystals

Qingfu CHEN, Wei CAI, Liancheng ZHAO   

  1. School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China
  • Received:2000-12-07 Revised:2001-02-23 Online:2001-09-28 Published:2009-10-10
  • Contact: Qingfu CHEN

Abstract: 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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