B2-10M (15R)-14M (7R) Successive Martensitic Transformations in Ni₅₀Al_xMn_50-x Alloys

¹ Institute of Materials Science, University of Tsukuba, 1-1 Tennodai, Tsukuba, Ibaraki 305, Japan
² National Institute for Research in Inorganic Materials, 1 Namiki, Tsukuba, Ibaraki 305, Japan

Abstract

By recent studies on Ni₅₀Al_xMn_50-x (16.0≤x≤20.5) alloys, various martensites, including new ones with long period stacking order structures, were found as a function of composition, and two DSC peaks were found for the composition 16.0≤x≤17.0. To examine the nature of the two DSC peaks, insitu observations of electron microscopy and x-ray diffraction during heating and cooling were carried out. Consequently the two DSC peaks were proved to represent the B2-10M-14M successive martensitic transformations.