PROCESS FOR MAKING THE SHAPE MEMORY ALLOY BASED ON FE BY THE POWDER METALLURGY

摘要

The invention relates to a process for obtaining a Fe-containing alloy with higher shape memory characteristics obtained by the powder metallurgy, namely by the mechanical alloying method. According to the invention, the process consists in mechanically alloying in ball mills or high energy planetary mills, in a protecting argon atmosphere, a powder mixture comprising 15 -30% Mn, 4 - 6.5% Si, 3 -10% Cr, 1-5% Ni and Fe for the remainder up to 100%, said percentage being expressed by weight, all powders having a purity of over 99.5%, the resulting mechanical mixture being cold pressed in various shapes under the action of some forces of 400...800 MPa, sintered in a furnace with controlled argon atmosphere at temperatures ranging from 1000...1200°C for 5 hours, cooled in the furnace, followed by plastic deformation by repeated hot rolling with cooling in water and finally teaching the alloy the shape memory by performing a number of 10...30 cycles of repeated loading-unloading in tension followed by heating and cooling, the shape memory effect reaching high values ranging from 4...6%.