NiMnGaTi铁磁形状记忆合金的马氏体相变和磁性能

Martensitic Transformation and Magnetic Properties of NiMnGaTi Ferromagnetic Shape Memory Alloy

对Ni53Mn23.5Ga23.5-xTix(x=0,2,5和8)系列合金的微观组织、马氏体相变及磁性能进行了研究,探究不同制备方法和不同Ti含量对合金性能的影响规律.研究结果表明:随着Ti含量的增加,合金的晶粒变细且析出物数量显著增加,适量的韧性第二相析出有助于改善合金的高脆性,合金的马氏体相变温度和饱和磁化强度均降低.EDS能谱分析表明,Ti掺杂合金的析出物是富Ni和Ti的第二相.对于Ti0和Ti2合金,900 r/min甩带样品的饱和磁化强度与铸态样品基本相同,但Ti5和Ti8甩带样品的磁化强度明显高于铸态,这是甩带工艺抑制非磁性的第二相析出所致.

The microstructure, martensitic transformation and magnetic properties of Ni53Mn23. 5Ga23. 5-xTix( x = 0,2,5 and 8) ferromagnetic shape memory alloys were studied to investigate the effects of different preparation methods and different Ti contents on the martensitic transformation and magnetic properties. The results show that when the Ti content increases,the grain size becomes finer, the martensitic transformation temperatures and martensitic transformation decrease,and the precipitate density increases where the appropriate amount of second-phase precipitations can facilitate to improve the high brittleness of the alloy. The EDS analysis indicates that in Ti doping alloys,the second-phase precipitation is rich in Ni and Ti constituents. The Ti addition decreases the saturation magnetization dramatically. The saturation magnetizations of Ti0 and Ti2 melt spun ribbons at the rotation speed of 900 r/min are almost the same as those of the as-cast samples. However,the saturation magnetizations of the Ti5 and Ti8 melt spun samples are obviously higher than those of the as-cast ones,because the non-magnetic second-phase precipitations are suppressed in the melt spun process.