Low temperature a/b nanotwins in Ni₅₀Mn_25+xGa_25-x Heusler alloys.

ABSTRACT: We have found low temperature a/b nanotwins having (110) twinning plane in a five-layered modulated martensite phase of Ni₅₀Mn_25+xGa_25-x (at. %) Heusler alloys and identified the particular region in phase diagram where the nanotwinning occurs. Evolution of the structure with decreasing temperature was studied by X-ray diffraction using single crystals exhibiting magnetic shape memory effect. The merging of (400) and (040) lines upon cooling for 2.6 < x < 3.5 indicated a/b nanotwinning originating from the refinement of initially coarse a/b twins. Refinement of the twins with decreasing temperature was observed directly using scanning electron microscopy. The prerequisite for nanotwinning is an extremely low twin boundary energy, which we estimated using fi

SUBMITTER: Straka L 

PROVIDER: S-EPMC6085376 | biostudies-literature | 2018 Aug

REPOSITORIES: biostudies-literature