The static and dynamic magnetic controlling characteristics of NiMnGa magnetically controlled shape memory alloy （MSMA） were experimentally studied. The results show that the characteristics of induced strain with r...The static and dynamic magnetic controlling characteristics of NiMnGa magnetically controlled shape memory alloy （MSMA） were experimentally studied. The results show that the characteristics of induced strain with respect to the magnetic field are nonlinear with saturation nature, and dependent on the temperature as well as the load applied to the MSMA. The magnetic shape memory effect can be observed only in complete martensite phase at room temperature. The magnetic permeability of MSMA is not constant and reduces with the increment of magnetic field. The relative saturation magnetic permeability of MSMA is about 1.5.展开更多
Microstructure,phase transformation and mechanical properties of NiMnGa particles/Cu composites prepared by spark plasma sintering method were investigated by SEM,EDS,XRD,susceptibility measurements and mechanical tes...Microstructure,phase transformation and mechanical properties of NiMnGa particles/Cu composites prepared by spark plasma sintering method were investigated by SEM,EDS,XRD,susceptibility measurements and mechanical tests.The NiMnGa particles were found to react with Cu matrix and the composites exhibited a similar crystal structure to the Cu matrix.The martensitic transformation and Curie transition of the composites were weakened due to the composition change of NiMnGa particles caused by reactions.With increasing NiMnGa particles content,the martensitic transformation and Curie transition of the composites were enhanced to some extent.However,the martensitic transformation temperature and Curie transition temperature were decreased by~50 K as compared to those of the original NiMnGa particles.The compressive strength of the composites increased with the increase of NiMnGa particles content,whereas the compressive strain was decreased gradually.展开更多
Composition and electron concentration dependence of transformation temperature in Ni2＋x＋y Mn1-xGa1-y, Ni2＋x Mn1-x Ga alloys with first order magnetic transition were studied. For Ni2 ＋ x ＋ y Mn1- x Ga1-y alloys,...Composition and electron concentration dependence of transformation temperature in Ni2＋x＋y Mn1-xGa1-y, Ni2＋x Mn1-x Ga alloys with first order magnetic transition were studied. For Ni2 ＋ x ＋ y Mn1- x Ga1-y alloys, martensitic transformation temperature TM increases and Curie temperature Tc decreases with the increase of electron concentration e/a, they intercept at e/a = 7.68. TM and Tc decrease when continue to increase electron concentration. While for Ni2＋x Mn1-xGa alloys, they cross at e/a = 7. 635. Before their crossing, the change tendency with e/a is the same as Ni2＋x＋yMn1-xGa1-y alloys;, after their crossing, both TM and Tc increase slowly. The different relations between TM and Tc and e/a within two NiMnGa alloys show that TM and Tc depend not only on e/a, but also on composition.展开更多
In order to realize a low-frequency and small-size underwater acoustic source,an underwater acoustic transducer has been designed by using Ni Mn Ga alloy, which has the advantages of large strain, rapid response and h...In order to realize a low-frequency and small-size underwater acoustic source,an underwater acoustic transducer has been designed by using Ni Mn Ga alloy, which has the advantages of large strain, rapid response and high energy density. Based on the deformation principle of Ni Mn Ga alloy, a physical model of a Ni Mn Ga longitudinal transducer is established, and the equivalentcircuit of the transducer is derived.A multi-physics coupling model of electromagnetic, mechanical and acoustic fields is established by using the finite element method to predict the underwater acoustic performance of the transducer.A small-scale prototype of the Ni Mn Ga longitudinal transducer is fabricated and its sound source level is tested in water within the frequency range from 500 Hz to 800 Hz. Experimental results demonstrate that the Ni Mn Ga transducer with an 8 mm diameter of the radiation surface, achieves sound source level of 115.5 d B at 700 Hz.展开更多
基金This work was supported by the National Natural Science Foundation of China under grant No.50177019by the Education Department of China under grant No.20040142004.
文摘The static and dynamic magnetic controlling characteristics of NiMnGa magnetically controlled shape memory alloy （MSMA） were experimentally studied. The results show that the characteristics of induced strain with respect to the magnetic field are nonlinear with saturation nature, and dependent on the temperature as well as the load applied to the MSMA. The magnetic shape memory effect can be observed only in complete martensite phase at room temperature. The magnetic permeability of MSMA is not constant and reduces with the increment of magnetic field. The relative saturation magnetic permeability of MSMA is about 1.5.
基金supported by the National Natural Science Foundation of China(No.51201044)High-level Scientific Research Guidance Project of Harbin Engineering University,China(No.3072022TS1006)+1 种基金Postdoctoral Scientific Research Developmental Fund of Heilongjiang Province,China(No.LBH-Q16046)Key Laboratory of Superlight Materials&Surface Technology(Harbin Engineering University),Ministry of Education,China.
文摘Microstructure,phase transformation and mechanical properties of NiMnGa particles/Cu composites prepared by spark plasma sintering method were investigated by SEM,EDS,XRD,susceptibility measurements and mechanical tests.The NiMnGa particles were found to react with Cu matrix and the composites exhibited a similar crystal structure to the Cu matrix.The martensitic transformation and Curie transition of the composites were weakened due to the composition change of NiMnGa particles caused by reactions.With increasing NiMnGa particles content,the martensitic transformation and Curie transition of the composites were enhanced to some extent.However,the martensitic transformation temperature and Curie transition temperature were decreased by~50 K as compared to those of the original NiMnGa particles.The compressive strength of the composites increased with the increase of NiMnGa particles content,whereas the compressive strain was decreased gradually.
文摘Composition and electron concentration dependence of transformation temperature in Ni2＋x＋y Mn1-xGa1-y, Ni2＋x Mn1-x Ga alloys with first order magnetic transition were studied. For Ni2 ＋ x ＋ y Mn1- x Ga1-y alloys, martensitic transformation temperature TM increases and Curie temperature Tc decreases with the increase of electron concentration e/a, they intercept at e/a = 7.68. TM and Tc decrease when continue to increase electron concentration. While for Ni2＋x Mn1-xGa alloys, they cross at e/a = 7. 635. Before their crossing, the change tendency with e/a is the same as Ni2＋x＋yMn1-xGa1-y alloys;, after their crossing, both TM and Tc increase slowly. The different relations between TM and Tc and e/a within two NiMnGa alloys show that TM and Tc depend not only on e/a, but also on composition.
基金supported by the National Natural Science Foundation of China (12074090, 11804067)。
文摘In order to realize a low-frequency and small-size underwater acoustic source,an underwater acoustic transducer has been designed by using Ni Mn Ga alloy, which has the advantages of large strain, rapid response and high energy density. Based on the deformation principle of Ni Mn Ga alloy, a physical model of a Ni Mn Ga longitudinal transducer is established, and the equivalentcircuit of the transducer is derived.A multi-physics coupling model of electromagnetic, mechanical and acoustic fields is established by using the finite element method to predict the underwater acoustic performance of the transducer.A small-scale prototype of the Ni Mn Ga longitudinal transducer is fabricated and its sound source level is tested in water within the frequency range from 500 Hz to 800 Hz. Experimental results demonstrate that the Ni Mn Ga transducer with an 8 mm diameter of the radiation surface, achieves sound source level of 115.5 d B at 700 Hz.
