An Energy Approach to Determine the Martensite Morphology in Nanocrystalline NiTi

作者:Petersmann Manuel*; Pranger Wolfgang; Waitz Thomas; Antretter Thomas
来源:Advanced Engineering Materials, 2017, 19(4): UNSP 1600684.
DOI:10.1002/adem.201600684

摘要

The characteristic features of martensite in nanocrystalline Ni-50at %Ti are a compromise between interface and strain energies introduced into the material when a grain transforms from austenite to a finely laminated martensite structure. This paper focuses on the evaluation of these energies. Whereas for grain sizes <100nm a single laminate is frequently observed, in larger grains the higher strain energy of this structure leads to hierarchical twinning. As the predominant contribution the strain energy is computed by the finite element method. Interface energies at the twin- as well as the grain-boundaries are subsequently added. Suitable scaling relations yield the evolution of twin spacing and predict that multiple laminates become favorable at a diameter range of 70-90nm.

  • 出版日期2017-4