The way composition affects martensitic transformation temperatures of Ni-Mn-Ga Heusler alloys

A systematic substitution of Ge, Si, C and Co for Ga in the non-stoichiometric Ni-Mn-Ga alloys was performed. The relationship between the compositions of different elements including Ni, Mn, Ga, Ge, Si, C, Co, In and martensitic transformation temperature (M-s) was studied in detail for the present alloys together with data collected from a variety of sources. It is found that M-s is a sensitive parameter to the composition. The size factor and electron concentration are usually thought to be the way the composition influences M-s in the Ni-Mn-Ga alloys. Here, analyzing by linear regression, the electron density maybe a most appropriate parameter to describe the way the composition influences M-s when compared with size factor and electron concentration. (C) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.