Project Abstract

THE PROJECT AIMS TO DEVELOP NEW CONSTRAINED RECOVERY APPLICATIONS OF FE-(MN,NI)-SI BASED SHAPE MEMORY ALLOYS (SMAS). THESE ALLOYS, WITH FIXING STRESSES ABOUT 500 MPA AND CLEARLY SUPERIOR TECHNOLOGICAL PROPERTIES (WORKABILITY AND WELDABILITY), AS COMPARED TO BETA TYPE SMAS (BASED ON TI OR ON CU), ARE THE CHEAPEST AMONG COMMERCIAL SMAS. THE TESTING OF SEVERAL ALLOY SYSTEMS, BASED ON THE CONCENTRATION FIELD FE-(28-32) (MN,NI)-(4-8)SI (WT.%) AND THE ANALYSE OF THE EFFECTS OF ALLOYING WITH CR, NI, CO, ETC., ON CORROSION RESISTANCE AND OF THE MICROADDITIONS OF CARBIDE FORMING ELEMENTS, ON THE PROPERTIES OF AUSTENITE MATRIX, ARE INTENDED TO BE PERFORMED. ON THE OTHER HAND, AS AN EFFECT OF COLLABORATING WITH THE POWDER METALLURGY (PM) LABORATORY FROM ISTANBUL TECHNICAL UNIVERSITY, IT IS PLANNED TO OBTAIN SOME CONNECTING-FIXING ELEMENTS WITH IDENTICAL SHAPES AND CHEMICAL COMPOSITIONS TO THOSE PRODUCED BY CLASSICAL TECHNOLOGY OF MELTING-CASTING-DEFORMATION AND TO COMPARE THE PROPERTIES OF THE APPLICATIONS MANUFACTURED BY THE TWO TECHNOLOGIES. THE ALLOYS WILL BE STRUCTURALLY ANALYZED - IN DIFFERENT STAGES OF THE CLASSICAL TECHNOLOGICAL PROCESS AND AT THE END OF PM PROCESS – BY OPTICAL AND ELECTRON METALLOGRAPHY, BY CALORIMETRIC AND DILATOMETRIC ANALYSIS AND BY TENSILE TESTING. SPECIAL EMPHASIS IS LAID ON THE STUDY OF THE FORMATION AND THE STRUCTURE OF BOTH EPSILON STRESS INDUCED MARTENSITE AND NANOPRECIPITATES (NANOCARBIDES) WITHIN AUSTENITE MATRIX. IT IS FORESEEN THAT, BY THE REDUCTION OF MARTENSITE PLATES WIDTH AND THE FORMATION AND EVEN DISTRIBUTION OF NANOCARBIDES, 3 ADVANTAGES ARE TO BE OBTAINED: (I) HARDENING OF THE AUSTENITE MATRIX; (II) SIMPLIFYING/ELIMINATING THE TRAINING THERMOMECHANICAL TREATMENT, WHICH IS STRICTLY NECESSARY FOR OBTAINING COMPLETE SHAPE MEMORY EFFECT IN FE-(MN,NI)-SI SMAS AND (III) THE POSSIBILITY FOR SCRAP IRON RECYCLING, OWING TO THE EFFECT OF CARBIDE FORMING ELEMENTS WHICH ENABLE CARBON CONTENT CONTROL AND REDISTRIBUTION IN AUSTENITE MATRIX.