Study On Transformation Behavior And Mechanical Properties Of FeMnSi/Fe Nanocomposites

Previous studies have shown that in the NiTi shape memory alloy(SMA)and nanowires composite material,during NiTi matrix occurs martensite transformation,the nanowires can show its intrinsic large elastic strain,thereby increasing the strength of the composite.However,NiTi SMA is expensive,and FeMnSi SMA is cheap,which is expected to replace NiTi SMA.In this paper,making FeMnSi SMA and industrial pure iron stacking-roll,and then through the wire drawing process,make industrial iron to nano-scale.The microstructures of the composites were analyzed by scanning electron microscopy(SEM)and transmission electron microscopy(TEM).The phase transition behavior and mechanical properties of the composites were studied by tensile and synchrotron radiation tests.The results show that:FeMnSi/Fe nanocomposites exhibited excellent plasticity and strength at 650?for 30min and then water quenched,and there is transformation clearly.After quenching,FeMnSi SMA in composites is a large amount of austenite at room temperature and a small amount of martensite.The results of synchrotron radiation show that during the stretching process,the austenite occurs stress induced martensitic transformation,and the elastic strain of Fe is 0.8%.In addition,as the diameter of the composite material decreases,it?s the proportion of austenite transformation is reduced,and the Fe size decreases and its lattice strain becomes larger,up to 1.0%.The results show that with the decrease of the tensile temperature,the yield strength increases first,then decreases,increases finally,and the plasticity decreases gradually,and the tensile strength increases gradually.The M_s~?point of the composite is about 120?and the M_S point is about-40?.The initial austenite content of the tensile samples at room temperature is more,and the initial austenite content at low temperature is less.As the stretching temperature gradually increases,the proportion of austenite transformation increases first and then decreases.In addition,at different stretching temperatures,the lattice strain limit of fcc(200)decreases gradually with increasing temperature,and the lattice strain limit of the other crystal faces increases with the temperature increasing.