Mechanical alloying of Nd-11Fe-Ti alloy and mechanical milling of NdFe_(11)Ti

The study revealed that the bait had a structure of D1 圯2. When the precursor of the wide source of nitrogen is introduced into the secondary chemical composition. Its saturation magnetization and, melon temperature rise National Natural Science Foundation of China funded project 59471022 received early, date received in 19990 revised version of the date of the year 19990927 Zuo introduction Shaolong. male. Born in 1963. Associate Professor. Doctor. Now, Department of Physics, Nanjing University, Nanjing 210093, the high and weak uniaxial anisotropy transforms into strong uniaxial anisotropy. Simultaneously. As a result, the rare earths contained in these compounds are relatively low. Ghost can be a candidate material for practical magnets.

however. It is difficult to synthesize butyl 12-structured, but hard-to-titanate at low temperatures. The reason is that the formation of low temperature, 17 structure of the 16 and 7 phases interfere with the formation of 1 gas in the heart 2 phase to get a 1 structure such as 12 valence, D 2 annealing temperature must be high plant 90031. The formation of the phase during the ball milling annealing process Many factors affect the 3,1, ray diffraction spectrum, such as ball mill conditions, alloy composition materials, the initial state of annealing temperature and time. Therefore, it is necessary to study the influence of these factors on the formation of NdFellTi phase. Understand the laws of generation. To lay the foundation for the development of permanent magnet materials based on 6.12,12.

Compared with the formation of the two phases in the annealing process of the plant 61 alloy.

1 Experimental method Mechanical alloying samples were recorded as samples. The raw materials used by the samples were 汜μm, which was in accordance with the Nd8-1 atomic ratio. The smooth compound for mechanical polishing is designated as No. B. The raw material for the NdFeTi atomic ratio is melted in a magnetron arc furnace under high-purity argon protection twice. The as-cast sample is packed in a quartz tube with PCT and kneaded. Under pure argon protection at 00, after homogenization treatment 48 water quench +, ray diffraction detection as a single phase as a structure, such as the deuteration points, which also has a temperature of 270 1. before mechanical grinding, will Xian 1 price The crude material was coarsely broken into powders of particle size 28,01. Mechanical alloying and mechanical grinding are performed on a high-energy ball mill. Each time the powder sample 8 is taken, the mass ratio of the ball material is 1. The ball mill jar containing the steel ball and the powder is evacuated to 2661503, and is filled with argon gas. Each sample ball milled 7 ball milled powder coating sample was annealed at a temperature range of sixty-five thousand ten thousand under the protection of high purity argon gas. The structure of the phase was measured by a 0,1 type ray diffractometer, and the temperature was measured by the AC initial susceptibility method. Using a differential thermal analyzer, Ding studied the phase transition during heating.

2 Experimental results and analysis at different temperatures Annealing 3, Shan, X-ray diffraction. From Wai, the ball milled after 7, except Ding, the main peak outside the broadening. A diffuse diffraction peak can be observed at a low turtle degree of 30 or so. It shows that 4 D 1 amorphous and nanocrystalline 6 D 1 solid solution have formed two phases; By Ding 1 original wide radius Big Yin 6 atomic radius, solid solution to 6 after. The iron cell expands and the diffraction peak shifts toward the lower turtle direction. The character constant increased from 28,661 to 0.2,888 melons. Calculated according to the law. Can be obtained Ding atom 5 According to the evaluation, his formula is obtained and Ding 1 crystal grain ten is 15 1. The ray diffraction spectrum is called. When the annealing temperature is 800. The occurrence of metastable phases 6, 17 and rare 621 and oxygen-rich rich annealing temperatures when 900 when. The intensity of the 6 columns of diffraction peaks decreases.

The occurrence of diffraction peaks at 20=33,37.5, etc., the NdFe and Ti7 phases begin to change, and the 2 phase transitions increase when the annealing temperature rises to 10,0,6 D. The intensity of the diffraction peaks decreases progressively, and the penalty of 12 peaks is taken. The intensity increases, and the amount of 12-phase transformation increases.

Because of the 7-phase and the 12-phase, only the 0 lines are very similar, and the peak overlap is more serious and can only be discerned by the nuances of the diffraction peaks when a transition occurs between the two phases. It is difficult to discriminate the degree of transition and the transition process + the measurement result of the initial susceptibility but can more clearly reflect the relationship between the initial ac susceptibility of the magnetic phase when annealing at different temperatures and the temperature. The temperature at each peak and valley is defined as the magnetic order transition temperature of the magnetic phase. When the annealing temperature is 800, there is a magnetic order transition temperature of 1850. The bright powder has been crystallized, 17 considerable annealing temperature rose to 900, when only a broad magnetic order transformation, 1 is also a temperature of 260, Ming The Dingxiang phase has begun to change continuously, and the cation phase is changed when the annealing temperature rises. At a temperature of 270, the Ming 6. Ding 17 phase has been completely transformed to form 16, D 2 phase.

Annealed at different temperatures, ray diffraction results. 4 out of sample 3 storage; lOOOC annealing, NdFe, Ding i7 phase has been completely transformed into NdFe, Qiu 12 compound, which 1 temperature is 2704.

Seventh, the progress of the phase transition process during the heating process was investigated, and the results of the differential thermal analysis of sweat temperature were 15.

Result 5. The team can. Samples 8 and 8 exhibit an amorphous crystallization exothermic peak at 620 and 638 inch, respectively. The results of ray diffraction and thermo-magnetic analysis measured by the present work show that the crystallization of the two phases in the D-phase stomach is a strong endothermic peak at 1202 ren. It is determined as, for, the 12-phase peritectic decomposition temperature, and the crystallization temperature. No obvious exothermic or endothermic observations were observed between the decomposition temperature and the decomposition temperature of hexane, which indicated that the transformation process of the dibutyl phase and the tetracene phase was slow.

The initial ac susceptibility and temperature curves for annealing at different temperatures after mechanical grinding 7 . From 3 can. After the ball milling 7, except for the presence of a broadened 1 1 1 diffraction peak outside the crystal, similar to the result of the mechanical alloying of butadiene 7, the Minted 1 compound was decomposed into non-product and 6 butadiene solid solution. When annealing below 900. The ray diffraction spectrum forms the sub-implicit only, 叽7 phase. In addition, Ding Shaohao's price is 2 dl 1 and rich phase. 900 annealing, ray diffraction and thermal magnetic curves are also 3,4; when the annealing temperature of Khan Sin Ding, 7 Xiang Xiang cane, Qiu 12 phase transformation 3, the thermal magnetic curve has two magnetic order transition temperature 4. Corresponds to the temperature of 6. D 17 and D 2 respectively. The results show that the two phases of the Ming 1000 annealing show that the phase transformation of the 1-butanium alloy powder formed by mechanical alloying and mechanical grinding has a great difference in the annealing process. its. The crystallization temperature is different, the former is about 620, and the latter is about 638.! 1 metastable, and, 7 can hear, the temperature of the 12 phase transition is different, the former is 900, the latter rose to 1000. Its meta-stable, turned 17 to the opposite, the team Ding 2 application process is different. In the former, there are two phases of coexistence between the seven phases of hearing and the phase transition to NdRTi12. These differences can be due to differences in the original distribution of non-products after ball milling. After mechanical alloying 71. Tiny atoms may not be very different in the distribution of non-goods, and in the mechanical grinding 6. Most of the 1 atoms are solid solution, 6 in. To make the amorphous phase lean in the near future, the non-equilibrium phase transition during the mechanical milling process of the 16-butane compound with a butane 2 structure was studied in detail. 141. It was found that the compound 6,1 is first transformed into disorder in the grinding process. Mixture of 7 phase and 0,6 butyl solid solution. Grinding continues, and the 17 phase turns into an amorphous phase. Since the Curie temperature of the NdFe and Ti7 phases obtained during the grinding process is very close to the Cuie temperature of the NdFe7 phase, the Ti content can significantly affect the temperature of the NdFe7 phase. Therefore, it is believed that 17 contains very few Ti atoms. As a result, NdFe and Ti7 are amorphized and are amorphous in lean T, while most of the original Titanium is dissolved in the precipitated medium. Based on this estimate, the phase transformation of Ding 1 in the first phase of Tang Shaolong's mechanical alloying 1 alloy and the mechanically grinded Yang 6 compound is 23! The actual solid solubility in the solution should be close to 20, and the solubility of the solid solution in the 6 in the equilibrium state of the large plant at 7, 0 hrs. 2. 2.3 The expansion of the solid solubility can be attributed to the increase of the dislocation density in the valence, and only nanometers. The phase transition of the D atom at the grain boundary is required to achieve the diffusion of atoms. The poor distribution of the Ding will inevitably affect the diffusion of the D atom, and the resulting phase formation is affected. The formation of a NdFe1Ti phase, which requires stable atomic fractions of about 7.7 Ti, is required.

The study of mechanical alloying and mechanical grinding of alloy powders was studied. All formed at low temperature annealing. D, 7 phase; When the annealing temperature is divided, it is half phase. According to thermodynamics, it can be concluded that when it is above 9000. NdFe. Phase 2 has become a thermodynamically stable phase. Two methods. The difference in the transition temperature and the difference in the transition process can be attributed to the kinetics of the transition. From the relationship between the hexagonal product 6, the Ding 17 phase and the Fangjing 0. Ding 12 phase. To achieve Yangyang. Ding, 7 opposite, Ding 2 phase change. It is only necessary to displace the D1 or 6 atom dumbbells in an orderly manner. D, a small part of the 7-phase 21 crystals are extremely similar on the column. Their overlapping of many strong peaks in the ray diffraction spectrum also shows this point. So you can think. The diffusion of D and A atoms plays a key role in the structural transformation. After mechanical alloying. Ding 1 atoms do not segregate in amorphous or 0. The micro-domain composition is relatively close to the 6-inch compound of Can, the 汜12-phase drive, or the 6-atom dumbbell continuous substitution, and they are 7-phase 2, 4 atoms on the crystal position. Due to the change of exchange between adjacent atoms after substitution, 6 temperature rises; at the same time, in the microscopic area. In the heart, the seven phases were replaced, the number of the original corpse was not the same, and the result was that the results of the magnetic ordering change, such as, Ding 2 phase. However, the hexamethylene 1 synthon is mechanically ground and most of the atoms are segregated in the middle. To achieve, the 12 phase change. The atom requires a longer distance when the annealing temperature is 90.

Long-distance diffusion is difficult to achieve, the result remains at 16, D 17 phase; when the annealing temperature is 1000, when. , And the original, the proliferation of enhanced, in the field of goods near 6 butadiene 1 solid solution into his 1 set, D 2 phase, away from the heart, the solid solution of the area is still kept by the poor 1 Can, published 7 phase. The two phases coexist 4; when the late flame temperature rises, the 1 and valence atomic diffusion energy is progressively enhanced, and short-time annealing can achieve long-distance diffusion, forming a price through disorder substitution, Ding 12 Ke.

3 Conclusions The phase transition during the annealing of mechanical alloy 6 and alloy 1 powders is different. The alloy powder obtained by mechanical alloying has a crystallization temperature of 620. Crystallization results in metastable 6. D, 7 mesh.

D, 12-phase mechanical grinding of the alloy powder. The crystallization temperature is 638. Can and Ding 7 phase should be at a high temperature of more than 1000 annealing, before they began to change to the Chan liver and the Qi 12 phase.