Tracing Memory in Polycrystalline Ferromagnetic Shape-Memory Alloys


  • This work is supported by the National Science Foundation International Materials Institutes (IMI) Program (DMR-0231320) with Dr. C. Huber as the Program Director, the National Natural Science Foundation of China (NSFC) (Grant No.s 50531020, 50325102, and 50528102), and the National Ministry of Education of China (with the NCET-04-0282). Use of the Advanced Photon Source was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Science, under Contract No. W-31-109-ENG-38. This work has benefited from the use of the Lujan Center at Los Alamos Neutron Science Center, funded by DOE Office of Basic Energy Sciences and Los Alamos National Laboratory funded by Department of Energy under contract W-7405-ENG-36. Supporting Information is available online from Wiley InterScience or from the author.


original image

In situ high-energy X-ray diffraction experiments reveal the influence of various microstresses and grain orientations on the memory effect in polycrystalline Ni2MnGa ferromagnetic shape-memory alloys during phase transformation (see figure). The “memory” of grain orientation and intergranular stress is evident; however, the microscale “memory” is degraded due to the existence of the intragranular stress.