Preparation And Magnetoelastic Properties Of Ce-based Light Rare Earth Transition Materials

The light rare-earth-based RFe₂ type rare earth-transition metal alloy has rich magnetic properties,has a very large magnetostrictive value at room temperature and is inexpensive,and has good application prospects.In this paper,light rare earth Ce-based(Tb_0.2Pr_0.8)_1-xCe_xFe_1.93 and(Pr_0.5Nd_0.5)_1-xCe_xFe_1.93 alloys were prepared mainly by arc melting and atmospheric pressure annealing;The Sm_0.88Nd_0.12Fe_1.80 alloy was prepared by mechanical alloying method,and the 1-3type and 0-3 type epoxy resin composite materials were fabricated by curing with and without a magnetic field.The crystal structure,easy magnetization direction,magnetic and magnetostrictive properties were investigated by X-ray diffraction(XRD),vibrating sample magnetometer(VSM)and static standard strain gauge.In the Ce-based RFe₂ type alloy,XRD analysis shows that partial substitution of Ce can suppress the appearance of the RFe₃ type iron-rich phase,which is conducive to the formation of a single Laves phase;And(Tb_0.2Pr_0.8)_1-xCe_xFe_1.93alloy,x?0.40 samples showed a single Laves phase structure,while no other impurity phases appeared.(Pr_0.5Nd_0.5)_1-xCe_xFe_1.93 alloy exhibits a mixed-valence behavior of non-single R³⁺valence.At a composition x=0.60,the lattice constant of the sample deviates from the linear Vegard's law;The Ms-x relationship curve of saturation magnetization and composition also shows a non-linear law,indicating that(Ce,R)mixed rare earth has mixed valence behavior;The XRD results of the magnetic field orientation samples indicate that the easy magnetization direction(EMD)of the alloy is along<111>axis at room temperature;Introducing Ce into the(Pr,Nd)Fe₂ system can reduce the magnetocrystalline anisotropy,thereby improving the anisotropic magnetostrictive properties under low field,(Pr_0.5Nd_0.5)_0.6Ce_0.4Fe_1.93alloy has good The low field magnetostrictive performance,under a magnetic field of 1 k Oe,l_a is 165 ppm.(Tb_0.2Pr_0.8)_1-xCe_xFe_1.93 alloy,the lattice parameter did not appear abnormal,but according to the Ms-x curve,x=0.80 deviated from the linear law,there is not enough evidence to explain in(Tb_0.2Pr_0.8)_1-xCe_xFe_1.93 alloy has mixed valence behavior.According to the aligned XRD sanmple,when the content of Ce x?0.50,the easy magnetization direction(EMD)of the alloy is along the<111>axis.When x=0.60,the EMD of the alloy has begun to deviate from the main axis.The normalized initial magnetization curve M/M_max-H and the normalized magnetostriction l_a/l_max-H curve show that the magnetocrystalline anisotropy compensation point of the alloy system is near x=0.60,and this alloy has good Low-field magnetostriction,la at 269 ppm under a 3 k Oe magnetic field.The effect of different annealing temperatures on the crystal structure and magnetostrictive properties of Sm_0.88Nd_0.12Fe_1.80 alloy were explored.XRD analysis shows that the alloy has the largest magnetostriction at an annealing temperature of 690?,and anisotropic magnetostriction l_areaches 1240 ppm.The pseudo 1-3 type composite with a 30 vol.%exhibit a large magnetostrictive value l_a=860 ppm.Especially in the low magnetic field(3 k Oe),the magnetostriction l_a reaches565 ppm,which is even greater than 75%of its sintered polycrystalline alloy,show that it has engineering application value.