Study On Nd₆₇Cu₃₃ And Nd_11.5Fe_81.8B_6.0Nb_0.7 Mixed Power Dieupset Magnet

In this paper,the dual alloy power was die-upset,?1-x?wt% Nd_11.5Fe_81.8B_6.0Nb_0.7+xwt% Nd₆₇Cu₃₃?x=0? 3? 6? 9? 12?,which effect of different additions of Nd₆₇Cu₃₃ alloy on the preferred orientation,microstructure and magnetic properties were investigated.According to the results,the alloy freed of both Dy and Ga were first hot-pressed and then hot-deformed,such as?1-x?wt% Nd_11.5Fe_81.8B_6.0Nb_0.7 + xwt% Nd₆₇Cu₃₃.The contribution of the volume percentage and thickness of the Rich-Rare-Earth grain-boundary phase and equivalent average grain size to above-mentioned alloys was calculated according to Nd-Fe-B phase diagram and V=1-a³/[?a+h?²?a+3h?] respectively.To research how Nd-rich grain boundary phase affect the coercive force of the ?1-x?wt% Nd_11.5Fe_81.8B_6.0Nb_0.7+xwt% Nd₆₇Cu₃₃.The results show that the anisotropy for the ?1-x?wt% Nd_11.5Fe_81.8B_6.0Nb_0.7+ xwt% Nd₆₇Cu₃₃ die-upset magnets which were deformed at Nd₆₇Cu₃₃ alloy power of 0wt%,3wt%,6wt%,9wt% and 12wt% with different additions of Nd₆₇Cu₃₃ alloy was improved.Besides,the peak intensity ratios I_?00l?/I_?214? of the hot deformed magnets are also increased from 0.39 to 5.87 under the increasing of Nd₆₇Cu₃₃ addition.The equivalent average grain size a of the ?1-x?wt% Nd_11.5Fe_81.8B_6.0Nb_0.7 + xwt% Nd₆₇Cu₃₃ die-upset magnets are calculated by Scherrer equation.The equivalent average grain sizes a are decrease from 254 nm to 143 nm,however,the coercive forces are increased.The microstructure of these hot deformation magnets which Nd₆₇Cu₃₃ alloy powers addition are less 9 wt% is disorder.There are so many equiaxed grains that lamellar grains are less.However,the microstructure of the dual alloy hot deformation magnets is improved when the additions of Nd₆₇Cu₃₃ alloy power are more than 9 wt%.There are more lamellar grains than less addition.The coercive forces of development tendency of those dual alloy hot deformation magnets are consistent with preferred orientation,increasing from 317 k A·m^-1 to 893 k A·m^-1.The result shows that added Nd₆₇Cu₃₃ alloy powers to lean-RE Nd-Fe-B magnets can enhance the coercive force.However,both remanence and maximum energy products are increase linearly when the content of the Nd₆₇Cu₃₃ addition is <6 wt.%,and then decrease when the content is over 6 wt.%.The best values of remanence and maximum energy products are 0.737 T and64.3k J·m-3 for the magnets with 6 wt.% Nd₆₇Cu₃₃ alloy addition.The research results show that the peak intensity of the 88wt% Nd_11.5Fe_81.8B_6.0Nb_0.7 + 12wt% Nd₆₇Cu₃₃ die-upset magnet is higher than?006?.The?004?peak intensity of other mixed power die-upset magnet is same as?006?.The contradictory phenomena needed to study.The volume percentages of the rich-RE grain-boundary phase are increased from 0% to 3.9%.179.50 k A·m^-1·%-1 is contributed to the coercive force improvement of the die-upset magnets?1-x?wt% Nd_11.5Fe_81.8B_6.0Nb_0.7+ xwt% Nd₆₇Cu₃₃ per the volume fraction.And those coercive forces are increased with both the thickness increase of the rich-RE GB phase from 0.67 nm to 1.31 nm,and the refinement of the equivalent average grain size a of the magnetic matrix from 254 nm to 143 nm.The calculated results show that non-ferromagnetic phase is increased with the volume percentage and thickness of the rich-RE GB phase,which enhance the isolation of the 2:14:1 grains and coercive force of the magnets.