MAGNETIC AND MARTENSITIC TRANSFORMATIONS IN NI50ALXMN50-X ALLOYS

The Ni-Al shape memory alloy system is well known by the unique charac teristics of phonon-softening and tweed, which are closely related to the B2-14M[(<5(2)over bar>2)(2)] martensitic transformation. If Mn is added to the alloy, additional martensite appears such as 10M[(<3(2)ov er bar>)(2)] long period stacking order structure. The magnetic and ma rtensitic transformations in the Ni50AlxMn50-x alloys were investigate d in order to understand their relations. This was accomplished by ext ensively utilizing various techniques such as magnetic susceptibility and magnetization measurements, transmission electron microscopy, diff erential scanning calorimetry (DSC) and electrical resistivity measure ments. These investigations uncovered strange successive magnetic tran sformations (antiferromagnetic to spin-glass state), which were examin ed further in relation to their martensitic counterparts. (C) 1998 Act a Metallurgica Inc. Published by Elsevier Science Ltd. All rights rese rved.