MAFHENIX

The aim of this project is to elaborate Heusler type materials Ni-Mn-X (X=Ga, In, Al, Sb, Sn) under different shapes and compositions and to study their multifunctional properties to realize an electromechanical mock up whose purpose is to estimate the feasibility of new electromechanical products introduction in the market. This project will focus on two main transformations that are the martensitic-austenitic transformation and the magnetic change (ferromagnetic –non magnetic). These two transformations are dependent on the temperature and the magnetic field and are conditioned upon the composition, the stoichiometric, the shaping and the quality of the material. Several devices such as circuit breakers, current limiters, filter chokes and micro contactors are expected from the coupled properties of these Heusler materials. One device upon them will be chosen and considered in more details after 20 months of this project according to the elaboration, the composition and the resulting properties. The results and simulations concerning the insertion and the behaviour of the device in the electrical network will allow to compare the different investigated routes. Our project is a whole research entity from the elaboration to the mock up construction. However, each thematic stand by itself and one can easily separate the material axis (elaboration of new composition crystals and films), the new manufacturing process (sheet elaboration of new composition) and the simulation and mounting of the mock up. Bulk materials will be realized under polycrystalline ingots, single crystals Ni-Mn-X (X=Ga, In, Al, Sb, Sn) or sheets Ni-Mn-X (X=Al, Sb, Sn) according to the process method, the stoichiometric composition and the expected coupled multifunctions. Thin films Ni-Mn-X (X=Al, Sb, Sn) will be elaborated mainly for microsystems and to study how the mechanical, thermal and magnetic properties are coupled in our experimental set up dedicated to that purpose. The referred elaborated sample will be characterized using classical and new experimental set up. The correlation between characteristic lengths (such as film or bulk thicknesses, grain size, distance between two successive twins) ,hysteresis (mechanical, magnetic and thermal) and the effect of elastic stress on the magnetization direction will be considered. The aim of these investigations relies on fundamental understanding of a new class of materials and on applied criterions for the use and insertion of these materials. Computer modelling will be performed to apprehend and simulate how the mechanical properties depends on the applied magnetic field and temperature and to simulate how the prospect device will be assembled and inserted in the network. The last point of our project is to realize a mock up so as to check if the principles and the coupling of the properties can be applied and can lead to a future device of circuit breakers, current limiters or filter chokes. Its unique value is to understand the industrial requirements for a future device and to help foresee the technical difficulties in the coupling of the properties, the assembly and mounting and not to realize an industrial device.