【摘要】 成功生长了Co50Ni21Ga29:Si(x=1,2)单晶样品,对其磁性,马氏体相变及其相关性质进行了细致的测量.发现掺Si成分的单晶具有非常迅速的马氏体相变行为、2.5%的大相变应变、大于100ppm的磁感生应变和4.5%的相变电阻.进一步研究指出,在CoNiGa合金中掺入适量Si元素,能够降低材料的马氏体相变温度,减小相变热滞后,提高材料的居里温度,并使得磁性原子的磁矩有所降低.尤其重要的是Si元素的添加能够增大材料马氏体的磁晶各向异性能,改善马氏体变体的迁移特性,从而获得更大的磁感生应变.更多还原

【Abstract】 In order to improve the properties of Co—Ni—Ga alloys,experiments of adding Si to Co_ 50Ni_ 21Ga_ 29 alloys were carried out to examine the effect of Si in quaternary Co_ 50Ni_ 21Ga_ 29Si_x(x1—2)alloys on their structure,martensitic transformation behavior and magnetic properties.The Co_ 50Ni_ 21Ga_ 29Si_x(x1,2)single crystals were successfully grown.All the samples with low Si doping show a sharp martensitic transformation with increasing temperature.The single crystal samples show a completely recoverable two-way shape memory with a strain of 2.5% upon the thermoelastic martensitic transformation.A large magnetic-field-induced strain of 110 ppm was measured at room temperature.A small quantity of Si doping can down-shift the martensitic transformation temperature,reduce the thermal hysteresis,decrease the magnetization but increase the Curie temperature.Especially,the Si doping can increase the magnetic anisotropy of Co—Ni—Ga-alloys,which is available to obtain large magnetic-field-induced strain in a low magnetic field.An electronic resistance “jump" of 4.5% upon the thermoelastic martensitic transformation was also reported.更多还原