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Effect of thermal treatment and ball milling on microstructure and phase transformation of Ni-Mn-Ga-Nb alloys 被引量:2
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作者 Jun-song WANG Bing TIAN +2 位作者 Yun-xiang TONG Feng CHEN Li LI 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2019年第10期2117-2127,共11页
To clarify phase transformation evolution of Nb-doped Ni-Mn-Ga bulk alloys after aging and ball milling, the microstructure and phase transformation of the aged and ball-milled dual-phase Nb-doped Ni-Mn-Ga alloys were... To clarify phase transformation evolution of Nb-doped Ni-Mn-Ga bulk alloys after aging and ball milling, the microstructure and phase transformation of the aged and ball-milled dual-phase Nb-doped Ni-Mn-Ga alloys were investigated by SEM, EDS, XRD, DSC and susceptibility measurements. The as-cast alloys were mainly composed of the second phase with layer-shape and presented a reduced martensitic transformation with increasing the second phase content. The second phase transformed from layer-shape to dense bar-shape and the martensitic transformation was enhanced after being quenched at 1173 K. After aging at 673 and 873 K, the 3% Nb alloy with less second phase exhibited a single-step phase transformation, whereas the 6% Nb and 9% Nb alloys with more second phase exhibited a two-step martensitic transformation and Curie transition. The martensitic transformation and Curie transition of the as-milled dual-phase particles disappeared and were retrieved after annealing at 1073 K due to the recovery of high ordered structure of the matrix. 展开更多
关键词 Ni-Mn-Ga-Nb alloy thermal treatment ball milling MICROSTRUCTURE phase transformation
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The influence of spark plasma sintering temperatures on the microstructure,hardness,and elastic modulus of the nanocrystalline Al-xV alloys produced by high-energy ball milling 被引量:2
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作者 J.Christudasjustus C.S.Witharamage +2 位作者 Ganesh Walunj T.Borkar R.K.Gupta 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2022年第27期68-76,共9页
Al-xV alloys(x=2 at.%,5 at.%,10 at.%)with nanocrystalline structure and high solid solubility of V were produced in powder form by high-energy ball milling(HEBM).The alloy powders were consolidated by spark plasma sin... Al-xV alloys(x=2 at.%,5 at.%,10 at.%)with nanocrystalline structure and high solid solubility of V were produced in powder form by high-energy ball milling(HEBM).The alloy powders were consolidated by spark plasma sintering(SPS)employing a wide range of temperatures ranging from 200 to 400°C.The microstructure and solid solubility of V in Al were investigated using X-ray diffraction analysis,scanning electron microscope and transmission electron microscope.The microstructure was influenced by the SPS temperature and V content of the alloy.The alloys exhibited high solid solubility of V–six orders of magnitude higher than that in equilibrium state and grain size<50 nm at all the SPS temperatures.The formation of Al3V intermetallic was detected at 400℃.Formation of a V-lean phase and bimodal grain size was observed during SPS,which increased with the increase in SPS temperature.The hardness and elastic modulus,measured using nanoindentation,were significantly higher than commercial alloys.For example,Al-V alloy produced by SPS at 200℃ exhibited a hardness of 5.21 GPa along with elastic modulus of 96.21 GPa.The evolution of the microstructure and hardness with SPS temperatures has been discussed. 展开更多
关键词 Spark plasma sintering Aluminum alloys Nanocrystalline alloys High-energy ball milling NANOINDENTATION HARDNESS Elastic modulus
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Effect of ball milling on hydrogen storage of Mg_3La alloy 被引量:3
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作者 董汉武 欧阳柳章 +1 位作者 孙泰 朱敏 《Journal of Rare Earths》 SCIE EI CAS CSCD 2008年第2期303-306,共4页
Hydrogen storage and microstructure of ball milled Mg3La alloy were investigated by X-ray diffraction and pressure-composition-isotherm measurement. The ball milled Mg3La alloy could absorb hydrogen up to 4wt.% at 300... Hydrogen storage and microstructure of ball milled Mg3La alloy were investigated by X-ray diffraction and pressure-composition-isotherm measurement. The ball milled Mg3La alloy could absorb hydrogen up to 4wt.% at 300 ℃ for the first time, along with a decomposing course. Following tests showed that the average reversible hydrogen storage capacity was 2.7wt.%. The enthalpy and entropy of dehydrogenation reaction of the decomposed ball milled Mg3La and hydrogen were calculated. XRD patterns indicated the existence of MgH2 and LaH3 in the decomposed hydride and the formation of Mg when hydrogen was desorbed. After the first hydrogenation, all the latter hydrogenation/dehydrogenation reactions could be taken place between Mg and MgH2. The ball milled Mg3La alloy exhibited better hydriding kinetics than that of the as-cast Mg3La alloy at room temperature. The kinetic curve could be well fitted by Avrami-Erofeev equation. 展开更多
关键词 hydrogen storage magnesium based alloys ball milling rare earths
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Bimodal-grained Ti fabricated by high-energy ball milling and spark plasma sintering
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作者 龙雁 郭文晶 李颖 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第4期1170-1175,共6页
Bimodal-grained Ti containing coarse and fine grains was fabricated by high-energy ball milling and spark plasma sintering (SPS). The microstructure and mechanical properties of the compacts sintered by Ti powders bal... Bimodal-grained Ti containing coarse and fine grains was fabricated by high-energy ball milling and spark plasma sintering (SPS). The microstructure and mechanical properties of the compacts sintered by Ti powders ball-milled for different time were studied. Experimental results indicated that when the ball-milling time increased, the microstructure of sintered Ti was firstly changed from coarse-grained to bimodal-grained structure, subsequently transformed to a homogeneous fine-grained structure. Compared with coarse-grained Ti and fine-grained Ti, bimodal-grained Ti exhibited balanced strength and ductility. The sample sintered from Ti powders ball-milled for 10 h consisting of 65.3% (volume fraction) fine-grained region (average grain size 1 μm) and 34.7% coarse-grained region (grain size > 5 μm) exhibited a compress strength of 1028 MPa as well as a plastic strain to failure of 22%. 展开更多
关键词 titanium alloy high-energy ball milling spark plasma sintering bimodal-grained structure
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Electrochemical performances of hydrogen storage alloys treated using a new milling technique
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作者 LIU Kaiyu ZHANG Ying +1 位作者 ZHANG Wei HE Yuehui 《Rare Metals》 SCIE EI CAS CSCD 2008年第3期273-277,共5页
A new self-made additive of amidocyanogen-acetic salt was used in wet ball-grind technique (WBGT) for preparing hydrogen storage alloys, and the effect on the electrochemical performance of the alloy electrode was i... A new self-made additive of amidocyanogen-acetic salt was used in wet ball-grind technique (WBGT) for preparing hydrogen storage alloys, and the effect on the electrochemical performance of the alloy electrode was investigated in detail. It was found that the prepared electrode had perfect electrochemical performances, such as rapid activation, high capability, high-rate discharge (HRD) ability, and good stability. The first discharge capacitance at 0.2 C (throughout this study, n C rate means that the rated capacity of a hydrogen storage alloy (full capacity) is charged or discharged completely in 1/n h) reached 278 mAh·g^-1 and the discharge capacitance reached the maximum of 322 mAh·g^-1 only after two charge-discharge cycles. For the dry method, wet method, and WBGT, the high rate discharge (HRD) values (C5 c/C0.2c ratio) were approximately 0.59, 0.76, and 0.83, respectively. The stable discharge capacity at 3 C increased from 275 mAh·g^-1 (dry method)to 295 mAh·g^-1 (WBGT). 展开更多
关键词 hydrogen storage alloys ball milling wet grinding electrochemical performance KINETICS
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Preparation of CNT/AlS i10Mg composite powders by high-energy ball milling and their physical properties
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作者 Lin-zhi Wang Ying Liu +3 位作者 Wen-hou Wei Xu-guang An Tao Zhang Ya-yun Pu 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2016年第3期330-338,共9页
This study investigated the effects of carbon nanotube (CNT) concentration on the micro-morphologies and laser absorption proper- ties of CNT/AlSi10Mg composite powders produced by high-energy ball milling. A scanni... This study investigated the effects of carbon nanotube (CNT) concentration on the micro-morphologies and laser absorption proper- ties of CNT/AlSi10Mg composite powders produced by high-energy ball milling. A scanning electron microscope, X-ray diffractometer, laser particle size analyzer, high-temperature synchronous thermal analyzer, and UV/VIS/NIR spectrophotometer were used for the analysis of micro- graphs, phases, granulometric parameters, thermal properties, and laser absorption properties of the composite powders, respectively. The results showed that the powders gradually changed from flake- to granule-like morphology and the average particle size sharply decreased with in- creases in milling rotational speed and milling time. Moreover, a uniform dispersion of CNTs in AlSi10Mg powders was achieved only for a CNT content of 1.5wt%. Laser absorption values of the composite powders were also observed to gradually increase with the increase of CNT concentration, and different spectra displayed characteristic absorption peaks at a wavelength of approximately 826 nm. 展开更多
关键词 metal matrix composites aluminum alloys carbon nanotubes powder metallurgy particle size distribution ball milling physi-cal properties
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Effects of ball milling time on porous Ti-3Ag alloy and its apatite-inducing abilities 被引量:3
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作者 侯乐干 李莉 郑玉峰 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第5期1356-1366,共11页
Ti and Ag powders were mixed with different ball milling time (1, 2, 5 and 10 h) and sintered into porous Ti-3Ag alloys. The samples were treated with hydrothermal treatment, and their apatite-inducing abilities wer... Ti and Ag powders were mixed with different ball milling time (1, 2, 5 and 10 h) and sintered into porous Ti-3Ag alloys. The samples were treated with hydrothermal treatment, and their apatite-inducing abilities were further evaluated by immersion in modified simulated body fluid. The results indicate that the high surface energy brought by powder refinement leads to the decline of Ag, but promotes the oxidation of Ti during the sintering process. Meanwhile, the hydrothermal treated porous Ti-3Ag alloys prepared by the powders ball milled for 10 h possess the best apatite-inducing ability. 展开更多
关键词 porous Ti-3Ag alloy hydrothermal treatment apatite-inducing ability ball milling time
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Effect of ball milling on microstructural evolution during partial remelting of6061 aluminum alloy prepared by cold-pressing of alloy powders 被引量:2
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作者 陈玉狮 陈体军 +1 位作者 张素卿 李普博 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第7期2113-2121,共9页
The effect of ball milling on the microstructural evolution was investigated during partial remelting of 6061 aluminum alloy prepared by cold-pressing of atomized alloy powders.The results indicate that the microstruc... The effect of ball milling on the microstructural evolution was investigated during partial remelting of 6061 aluminum alloy prepared by cold-pressing of atomized alloy powders.The results indicate that the microstructural evolution of 6061 aluminum alloy can be divided into three stages,the dissolution of eutectic phases and the coarsening and growth behavior of the resulting grains,structural separation and spheroidization of primary particles,and the final coarsening behavior of the particles.Compared with the alloy without ball milling,ball milling accelerates the first stage of microstructural evolution due to the energy stored in the powders,but the latter two stages are slowed down because of the formation of large-sized powders.Moreover,the finer the as-cold-pressed microstructure is,the smaller and more spherical the primary particles in the final semisolid microstructure are.Furthermore,properly elevating the heating temperature is beneficial for obtaining small and spheroidal particles. 展开更多
关键词 6061 aluminum alloy ball milling powder thixoforming partial remelting microstructural evolution
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Structural and Electrochemical Characteristics of Mg_(0.94)La_(0.06)Ni Alloy Prepared by Ball Milling 被引量:4
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作者 蒙冕武 刘心宇 周怀营 《Journal of Rare Earths》 SCIE EI CAS CSCD 2004年第5期673-677,共5页
The amorphous Mg_(0.94)La_(0.06)Ni alloy was synthesized by ball milling for different time at 400 r·min^(-1). Electrochemical performances of the alloy electrodes were investigated and the results show that the ... The amorphous Mg_(0.94)La_(0.06)Ni alloy was synthesized by ball milling for different time at 400 r·min^(-1). Electrochemical performances of the alloy electrodes were investigated and the results show that the specimens would reach their maximum electrochemical discharge capacities at the first charge/discharge cycle. The cyclic tests and X-ray diffraction (XRD) results show that discharge capacities would decrease rapidly due to the crystallization of the amorphous and the oxidization of magnesium on the particle surface during the electrochemical charge/discharge cycling. In addition, the DTA and SEM results reveal that the thermal stabilities will be improved and the size of the alloy will be decreased with the ball-milling time. The amorphous Mg_(0.96)La_(0.04)Ni alloy prepared by ball milling for 40 h at 400 r·min^(-1) shows the best electrochemical properties. 展开更多
关键词 hydrogen storage alloy electrochemical properties ball milling Mg-Ni hydride AMORPHOUS rare earths
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Microwave Permeability Change of FeCo Nanocrystalline During High Energy Ball Milling 被引量:3
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作者 王维 官建国 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2006年第1期16-18,共3页
The microwave magnetic properties of the ball milled FeCo panicles were investigated as functions of ball milling time ( t ) using microwave electromagnetic parameters analysis techniques. The results show that the ... The microwave magnetic properties of the ball milled FeCo panicles were investigated as functions of ball milling time ( t ) using microwave electromagnetic parameters analysis techniques. The results show that the imaginary part of intrinsic dynamic permeability ( ui ) of the ball- milled panicles is much bigger than that of raw powders. ui strongly depends on t and exhibits several slightly damped ferromagnetic resonances. These phenomena are in qualitative agreement with the formation of the corresponding microstructure or the Aharoni ' s model of non-uniform exchange resonance modes. The present microwave permeabilhy behavior indicates that nanocrystalline materials with the same grain size may exhibit different properties that depend upon the microstructure, which provides a possibility for manufacturing high performance microwave absorber. 展开更多
关键词 high energy ball milling carbonyl iron COBALT ALLOY NANOCRYSTALLINE microwave electromagnetic parameters
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Spark plasma sintering of a high-energy ball milled Mg-10 wt% Al alloy 被引量:5
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作者 M.U.F.Khan A.Patil +2 位作者 J.Christudasjustus T.Borkar R.K.Gupta 《Journal of Magnesium and Alloys》 SCIE 2020年第2期319-328,共10页
The influence of spark plasma sintering(SPS)temperature on microstructure,hardness and corrosion behavior of a high-energy ball milled Mg-10wt%Al alloy was investigated in this work.The holding time and sintering pres... The influence of spark plasma sintering(SPS)temperature on microstructure,hardness and corrosion behavior of a high-energy ball milled Mg-10wt%Al alloy was investigated in this work.The holding time and sintering pressure for SPS were kept constant while varying the sintering temperature from 200 to 350℃.The grain size and microstructure were studied using X-ray diffraction analysis,scanning electron microscopy,energy dispersive X-ray spectroscopy,and Archimedes'based density measurement.Corrosion behavior was investigated using potentiodynamic polarization tests.The nanocrystalline regime(grain size<100nm)was maintained even after SPS up to 350℃.The density of the alloy increased with increasing the SPS temperature.Vickers'hardness and corrosion performance improved up to 300℃ followed by a decrease after SPS at 350℃.Possible reasons for densification,strengthening,and corrosion behavior have been discussed in the light of reduced porosity and microstructural changes. 展开更多
关键词 Nanocrystalline alloy MAGNESIUM High energy ball milling Spark plasma sintering CORROSION
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Hydrogen storage performances of as-milled REMg_(11)Ni(RE=Y, Sm) alloys catalyzed by MoS_2 被引量:2
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作者 Yang-huan ZHANG Wei ZHANG +4 位作者 Ze-ming YUAN Wen-gang BU Yan QI Xiao-ping DONG Shi-hai GUO 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2018年第9期1828-1837,共10页
To compare the hydrogen storage performances of as-milled REMg11Ni-5MoS2(mass fraction)(RE=Y,Sm)alloys,which were catalyzed by MoS2,the corresponding alloys were prepared.The hydrogen storage performaces of these allo... To compare the hydrogen storage performances of as-milled REMg11Ni-5MoS2(mass fraction)(RE=Y,Sm)alloys,which were catalyzed by MoS2,the corresponding alloys were prepared.The hydrogen storage performaces of these alloys were measured by various methods,such as XRD,TEM,automatic Sievert apparatus,TG and DSC.The results reveal that both of the as-milled alloys exhibit a nanocrystalline and amorphous structure.The RE=Y alloy shows a larger hydrogen absorption capacity,faster hydriding rate,lower initial hydrogen desorption temperature,superior hydrogen desorption property,and lower hydrogen desorption activation energy,which is thought to be the reason of its better hydrogen storage kinetics,as compared with RE=Sm alloy. 展开更多
关键词 Mg-based alloy ball milling CATALYST rare earth element hydrogen storage performance
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Energy analysis of mechanical alloying of molybdenum disilicide in a new-type high energy vibrating ball mill 被引量:2
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作者 FENG Pei-zhong WANG Xiao-hong +1 位作者 QIANG Ying-huai QU Xuan-hui 《Journal of China University of Mining and Technology》 EI 2008年第3期449-453,共5页
In order to understand the fundamentals of a high energy vibrating type milling process, the energy transfer during me-chanical alloying of molybdenum disilicide is investigated based on the Magini-Iasonna energy tran... In order to understand the fundamentals of a high energy vibrating type milling process, the energy transfer during me-chanical alloying of molybdenum disilicide is investigated based on the Magini-Iasonna energy transfer method, amended by Murty. The efficiency factor and total energy of milling are calculated. MoSi2 synthesized by a mechanically induced self-propagating reaction has also been studied according to different milling parameters, such as the number of balls and the ball to powder weight ratio. The results indicate that the efficiency factor is between 1.944 and 8.507 J/(g·s). A total milling energy of about 19.38–26.47 kJ/g is found to be necessary for the mechanically induced self-propagating reaction of a Mo:2Si powder mixture. The efficiency of milling energy transfer is about 3.3%–4.5%. The experiment and modeling show that the optimum condition for mechanical alloy-ing is a half full vial of balls. 展开更多
关键词 mechanical alloying high-energy ball mill energy analysis MODELING
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Multirange Fractals in Materials: Applications to Fracture and Mechanical Alloying under Ball Milling 被引量:1
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作者 Chiwei LUNG(International Centre for Materials Physics, Institute of Metal Research,Chinese Academy of Sciences, Shenyang 110015, China) 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1997年第4期255-259,共5页
A new model of multirange fractals is proposed to explain the experimental results observed on the fractal dimensions of the fractured surfaces in materials. A new explanation to the Williford's multifractal curve... A new model of multirange fractals is proposed to explain the experimental results observed on the fractal dimensions of the fractured surfaces in materials. A new explanation to the Williford's multifractal curve on the relationship of fractal dimension with fracture properties in materials has been given. It shows the importance of fractorizing out the effect of fractal structure from other physical causes and separating the appropriate range of scale from multirange fractals. Mechanical alloying process under ball milling as a non-equilibrium dynamical system has been also analyzed. 展开更多
关键词 ball Applications to Fracture and Mechanical Alloying under ball milling Multirange Fractals in Materials
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XRD and HRTEM Analyses of the Ball Milled Nanocrystalline FeCo Alloy
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作者 王琦 官建国 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2006年第1期68-71,共4页
The nanostractures of the ball milled FeCo particles were characterized as functions of the ball milling time ( t ) using quantitative X- ray diffraction ( XRD ), high resolution transmission electron microscopy ... The nanostractures of the ball milled FeCo particles were characterized as functions of the ball milling time ( t ) using quantitative X- ray diffraction ( XRD ), high resolution transmission electron microscopy (HRTEM) analysis techniques. The results show that the nanocrystalliue bcc FeCo particles are available using carbonyl iron and cobalt powders as the start materials during the high-energy ball milling. At the early stage of ball milling, Co powders are easily mashed into nanocrystalllites, by which the surface of the larger Fe particles of about 80- 150 nm is coated. With t increasing, the refinement of grain size and the incorporation of defects including dislocations, disclinations and grain boundaries happen, and then FeCo alloy with a certain layered structure is formed, finally the layered stractare disappears with the formation of isotropic grains having a steadystate grain size in the nanometer regime after a certain period of t. 展开更多
关键词 high energy ball milling carbonyl iron COBALT ALLOY nanocrystalline materials
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PREPARATION AND CATALYTIC ACTIVITY OF AMORPHOUS Ni-Pd-Si ALLOY POWDER BY BALL MILLING
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作者 ZHANG Haifeng, LIJie, SONG Qihong, HU ZhuangqiInstitute of Metal Research, Chinese Academy of Sciences, Shenyang, ChinaLI WenShenyang Institute of Technology,Shenyang. China Manuscript received 26 April, 1994 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1994年第2期129-132,共4页
Amorphous Ni-Pd-Si ribbons were partially crystallized by relaxation treatment then secondary amorphous Ni-Pd-Si alloy powder prepared by mechanical milling. The surface states of amorphous and crystalline Ni-Pd-Si po... Amorphous Ni-Pd-Si ribbons were partially crystallized by relaxation treatment then secondary amorphous Ni-Pd-Si alloy powder prepared by mechanical milling. The surface states of amorphous and crystalline Ni-Pd-Si powders were studied by XRD, TEM, AES and ESCA spectra. The catalytic activities of amorphous and crystalline powders in hydrogenation of styrene was measured.The result shows that the catalytic activity of amorphous Ni-Pd-Si powder was higher than that of crystalline one by 6 times in hydrogenation of styrene. 展开更多
关键词 Ni-Pd-Si alloy ball milling hydragenation
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Manufacturing a TiAl alloy by high-energy ball milling and subsequent reactive sintering
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作者 QU Shengguan LI Xiaoqiang +2 位作者 LI Yuanyuan HU Lianxi WANG Erde 《Rare Metals》 SCIE EI CAS CSCD 2006年第1期21-26,共6页
A TiAl alloy was fabricated by high-energy ball milling and subsequent reactive sintering from the mixed powders of Ti and Al. High-energy ball milling produced a kind of particular composite powders with an extremely... A TiAl alloy was fabricated by high-energy ball milling and subsequent reactive sintering from the mixed powders of Ti and Al. High-energy ball milling produced a kind of particular composite powders with an extremely fine altemative Ti and Al lamella structure. The composite powders not only possessed good consolidation and densification characteristics, but also resulted in the augment of nucleation rate of α and γ titanium aluminides during solid-phase reactive sintering After a series of processing, pressing, degassing, extrusion, and sintering, the resultant TiAl alloy presented high relative density and refined grain sizes of (α2 + γ) lamella and γ phases. The compressive yield strength of the sintered TiAl reached 600 MPa at 800℃. 展开更多
关键词 TiAl alloy high-energy ball milling reactive sintering
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A comparison study of hydrogen storage performances of SmMg_(11)Ni alloys prepared by melt spinning and ball milling
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作者 Yanghuan Zhang Meng Ji +4 位作者 Zeming Yuan Jingliang Gao Yan Qi Xiaoping Dong Shihai Guo 《Journal of Rare Earths》 SCIE EI CAS CSCD 2018年第4期409-417,共9页
The melt spinning(MS) and ball milling(BM) technologies are thought to be efficient to prepare nanostructured Mg and Mg-based alloys for improving their hydrogen storage performances. In this paper, two technologi... The melt spinning(MS) and ball milling(BM) technologies are thought to be efficient to prepare nanostructured Mg and Mg-based alloys for improving their hydrogen storage performances. In this paper, two technologies, viz. melt spinning and ball milling, were employed to fabricate the SmMg_(11)Ni alloy. The structure and hydrogen storage performance of these two kinds of alloys were researched in detail. The results reveal that the as-spun and milled alloys both contain nanocrystalline and amorphous structures. By means of the measurement of PCT curves, the thermodynamic parameters of the alloys prepared by MS and BM are ΔN_(Ms)(des) = 82.51 kJ/mol and ΔH_(BM)(des) = 81.68 kJ/mol, respectively, viz.ΔH_(MS)(des) 〉 ΔH_(BM)(des). The as-milled alloy shows a larger hydrogen absorption capacity as compared with the as-spun one. The as-milled alloy exhibits lower onset hydrogen desorption temperature than the as-spun one. As to the as-milled and spun alloys, the onset hydrogen desorption temperatures are557.6 and 565.3 K, respectively. Additionally, the as-milled alloy shows a superior hydrogen desorption property than the as-spun one. On the basis of time that required by desorbing hydrogen of 3 wt% H_2, the as-milled alloy needs 1488.574,390 and 192 s corresponding to hydrogen desorption temperatures 593,613,633 and 653 K, while the as-spun alloy needs 3600,1020,778 and 306 s corresponding to the same temperatures. The dehydrogenation activation energies of the as-milled and spun alloys are 100.31 and105.56 kJ/mol, respectively, the difference of which is responsible for the much faster dehydriding rate of the as-milled alloy. 展开更多
关键词 Mg-based alloy Melt spinning ball milling Hydrogen storage kinetics Comparison Rare earths
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Mechanically activated disproportionation of NdFeB alloy by ball milling in hydrogen 被引量:2
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作者 胡连喜 石刚 王尔德 《中国有色金属学会会刊:英文版》 CSCD 2003年第5期1070-1074,共5页
Mechanically activated disproportionation of Nd 12 Fe 82 B 6 alloy by ball milling in hydrogen atmosphere was experimentally investigated. The aspects of thermodynamics and kinetics for the mechanically activated disp... Mechanically activated disproportionation of Nd 12 Fe 82 B 6 alloy by ball milling in hydrogen atmosphere was experimentally investigated. The aspects of thermodynamics and kinetics for the mechanically activated disproportionation of the NdFeB alloy were discussed. Both the evolution of the disproportionation reaction and the corresponding microstructure change of the alloy during milling were characterized by X ray diffraction (XRD) analysis. The results show that the matrix phase Nd 2Fe 14 B of the as cast Nd 12 Fe 82 B 6 alloy can be disproportionated into a mixture of Nd hydride (H 5Nd 2), FeB/Fe 2B, and α Fe, by ball milling under hydrogen pressure of 0.2 MPa. The as disproportionated phases are of the size about 20 nm, suggesting that ball milling in hydrogen is an effective route for low temperature disproportionation processing of the NdFeB alloy to ensure a full nano structured as disproportionated microstructure. This is the basis for synthesizing Nd 2Fe 14 B/ α Fe nano composites with magnetic exchange coupling effect by subsequent desorption recombination processing. 展开更多
关键词 铌铁硼合金 纳米结构相 球磨研磨 磁铁
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Effect of post annealing on phase transformation of Ni-Mn-Ga ferromagnetic shape memory alloy particles prepared by ball milling
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作者 田兵 陈枫 +1 位作者 李莉 郑玉峰 《中国有色金属学会会刊:英文版》 CSCD 2007年第A02期630-633,共4页
The effect of post annealing on the phase transformation of Ni52Mn24Ga24 ferromagnetic shape memory alloy particles prepared by ball milling was studied. Ni52Mn24Ga24 alloy particles at micron scale were prepared succ... The effect of post annealing on the phase transformation of Ni52Mn24Ga24 ferromagnetic shape memory alloy particles prepared by ball milling was studied. Ni52Mn24Ga24 alloy particles at micron scale were prepared successfully by ball milling the crushed bulk alloy. SEM observation reveals that the shape of the as-milled particle is regular polygon and a lot of cracks can be seen at the surface of the particles. For as-milled particles,the widening of characteristic peak can be found in the XRD pattern,and no transformation characterization can be detected by DSC. Post annealing at the elevated temperature will recover the transformation behavior of milled particles to the same level as that of bulk sample. It is shown that with increasing annealing temperature above 400 ℃,Ms decreases and As increases,while the magnetic transition temperature keeps constant. XRD results indicate that the change of grain size of the particles results in such an effect of post annealing. 展开更多
关键词 镍锰镓合金 开卷记忆合金 退火 相变 球磨
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