| Fe-Mn-Si based shape memory alloy has the advantages of low price, good processability, good mechanical performance, high phase transition point, large thermal hysteresis etc., however, compared with the Ni-Ti shape memory alloy, the shape memory effect is relatively low, poor corrosion resistance, which has become a major obstacle to the application and development of the. In practical applications, the use of memory alloy environment is complex, which leads to the choice of shape memory alloy, but also to consider the state of corrosion resistance. In order to improve the shape memory effect of Fe-Mn-Si based shape memory alloy, the solid solution treatment, rapid solidification, thermal mechanical cycle training on Fe Mn Si based shape memory alloy processing, by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) studied solid solution treatment, rapid solidification, thermal mechanical cycling of Fe-Mn-Si based shape memory alloy shape memory effect the influence law and mechanism. At the same time, the influence of size effect on the shape memory effect. Corrosion resistance of Fe-Mn-Si based shape memory alloy was studied by electrochemical corrosion test and weight loss method:(1)Shape memory effect of Fe-Mn-Si alloy increased with increasing solution temperature increased first and then decreased trend, optimal solution temperature is 973k. The research shows that, the low temperature shape memory effect of Fe Mn Si alloy increased mainly because of grain shape change result should force induced e-martensite growth resistance is reduced; the shape memory effect of late decreased because of grain growth and the second phase dissolved.(2)Rapid solidification can significantly refine the grain size of Fe-Mn-Si shape memory alloy, as cast grain diameter of about 60 um, after rapid solidification of the grain diameter of about 20 m. Rapid solidification can significantly improve the shape memory effect of Fe-Mn-Si shape memory alloy, and the shape memory effect of rapid solidification material is higher than that of as cast material under various pre deformation. But different pre deformation quantity, shape memory effect to raise the ratio is, the low pre deformation, shape memory effect increased by about 24%; high pre deformation and improve significantly higher, about 160%increase about. Analysts believe that the rapid solidification processing to improve the shape memory effect of Fe-Mn-Si alloy mainly because of the rapidly solidified samples have more grain boundaries, stacking faults and higher strength of the matrix, resulting in a more force induced e martensite.(3)The effect of the number of thermal mechanical cycles on the shape memory effect of the as cast and rapidly solidified materials was consistent. The effect of training times on the shape memory effect of Fe-Mn-Si shape memory alloys of two kinds of state was firstly increased and then decreased, and the training effect was the best, and the level of pre deformation was two. The shape memory effect of as cast Fe-Mn-Si system can reach about 38%, and the solid state can reach about 55%. Analysis shows that the thermal mechanical cycle training can improve the shape memory effect is the main source in the training process produced a stacking fault this is to produce more should force induced e martensite defects.(4)Under the same pre deformation, the larger the sample size, the lower the shape memory effect. This phenomenon is mainly due to the same pre deformation case, large sample size the more force induced e martensite cross, the study found. The shape memory effect of the same size sample decreases with the increase of pre deformation, which is mainly due to the increase of plastic deformation.(5)Compared with as cast Fe-Mn-Si based shape memory alloy, the corrosion resistance of rapid solidification materials in HCl solution is relatively good, and the corrosion resistance of NaOH solution is relatively poor. The corrosion resistance of Fe-Mn-Si shape memory alloy in NaOH solution was better than that in HC1 solution, and the corrosion resistance of the shape memory alloy was better than that in each kind of corrosion solution, and the corrosion resistance of the shape memory alloy was relatively low. The corrosion resistance of the memory alloy after thermo mechanical cycling training was lower than that of the non trained alloy, and the corrosion resistance of the alloy was decreased with the increase of the cycle times. In high temperature and high pressure corrosion environment, the corrosion resistance of Fe-Mn-Si based shape memory alloy is higher than that of 304 stainless steel, and the corrosion resistance of is not changed with the increase of temperature. |
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