Study on Composition Optimization and Memory Performance of Fe-Mn-Si SMA

Study on Composition Optimization and Memory Performance of Fe-Mn-Si SMA
　　Fe-Mn-Si series shape memory alloys in iron-based memory alloys had been produced by using low raw material, ordinary induction furnace, special smelting technology, and the effect of Cr, Ni, C, RE on the mechanical properties and memory effect had been discussed by means of method of orthogonal experiment, and the result indicated that properties of alloys were greatly affected by Cr Ni C. Mechanical properties decreased with the increasing C content when C content was less than 0.3%, and increased when C content was more than 0.3%. Shape memory effect of alloys decreased rapidly when the C content was increased. The increasing Cr was beneficial to Cube neodymium magnet the shape memory effect and mechanical properties of alloys. Both mechanical properties and shape memory effect decreased slightly when the Ni content was increased. Tensile properties increased with the increasing Rare Earth content.
　　The impact properties and shape memory effect decreased with the increasing RE content when the RE content was less than 0.1%, and increased when the RE content was more than 0.1%. Analyzed comprehensively, the optimum composition was 0.2%C, 15%Mn, 5%Si, 10%Cr.Second, the best composition was optimized by orthogonal design method, and the effect of factors of pre-deformation, thermal mechanical training, restoring temperature, quenching temperature on the memory effect of alloys was discussed. It had been found that the shape recovery ratio of the alloy decreased with increasing pre-deformation, and being relative to the pre-deformation it had a stationary zone (2.78%~4.17%) in which shape recovery ratio varied slightly, and the memory effect was stable, and shape recovery ratio decreased rapidly with the increasing pre- deformation when pre-deformation was out of this range, more or less. Shape recovery ratio of alloy increased with the http://www.chinamagnets.biz/ increasing restoring temperature, and when the temperature reached to 650℃,the variation of memory recovery ratio was stable. Shape recovery ratio increased obviously with the increasing thermal-mechanical training times; however, it slightly decreased when the training came to certain times which was related to alloy composition. The better shape recovery ratio can not be obtained when the quenching temperature was low to certain level, and can be obtained when the quenching temperature was in given range which was wide and was different according to the varying composition of alloy.Finally, the electrochemical corrosion test of alloy with 0.2%C, 15%Mn, 5%Si, 10%C indicated that this shape memory alloy was liable to passivation, and it had low passivation potential and large passivation region, in addition its passive film was stable and its electrochemical corrosion resistance was equal to stainless steel.