共查询到19条相似文献,搜索用时 171 毫秒
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机械合金化制备Nd60 Fe20 Al10 Co10非晶粉末的研究 总被引:1,自引:0,他引:1
利用机械合金化制备Nd60Fe20Al10Co10非晶粉末,采用X射线衍射(XRD)和振动样品磁强计(VSM)研究Nd60Fe20Al10Co10非晶的形成过程、磁性能变化及其与成分结构的关系。结果表明,90min后Al原子溶入Nd原子形成固溶体。球磨2h后出现少量非晶,20h后Co单质和Nd单质消失.组织为非晶相(含少量的α-Fe)。球磨100h最终得到非晶 少量的α-Fe纳米晶。球磨过程中,矫顽力随着合金中非晶的量增加而升高.球磨20h矫顽力达到43kA/m。Nd60Fe20Al10Co10合金具有硬磁性是由于非晶相的存在而造成的。 相似文献
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为开发新型金属材料,采用机械合金化与放电等离子烧结的方法制备Fe-Fe3Al合金.根据Fe-Al二元相图与研究经验,对成分及工艺进行优化设计.用X射线衍射仪(XRD)对成分进行了定性分析,用扫描电子显微镜(SEM)观察了样品的表面与断口形貌,进行了能谱分析,并测试了致密度、显微硬度(HV)及抗弯强度、抗拉强度等力学性能.结果表明:对粉末进行预球磨,并在球磨前后对粉末进行搅拌混合处理,能更好地促使Fe与Al在高能球磨的过程中反应;经放电等离子烧结能够制备出Fe3Al/Fe两相材料,相对密度为99%以上,硬度为HV561,抗弯强度1426 MPa,抗拉强度640 MPa,力学性能优于文献报道的值. 相似文献
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球磨诱发α-Fe粉与间苯二胺混合物的固相反应 总被引:1,自引:0,他引:1
研究了球磨α-Fe粉末与间苯二胺混合时发生的固相反应以及铁氮化物的形成机理,在球磨过程中,随着球磨时间的延长α-Fe粉末与间苯二胺混合发生的相变为α-Fe→α′-Fe(N)→ε-F2-3N,球磨250h后,可得到含有11.53%N(质量分子)的过饱和ε-Fe2-3N相,它在512℃以下是稳定的,其饱和磁化强度为814.4emu/g,剩磁为33.8emu/g,矫顽力为16.3kA/m.与固-气反应相比,用固-固反应制备ε-Fe2-3N相的效率更高。 相似文献
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机械球磨Ti—Al复合粉扩散反应的影响 总被引:4,自引:0,他引:4
研究了粉末烧结制取Ti-Al金属间化合物过程中,机械球磨对Ti,Al混合粉扩散反应的影响,结果表明,机械球磨使Ti,Al混合粉形成具有层片结构的复合粉,且球磨时间越长,层片越薄越均匀,在固相下对不同球磨时间的Ti,Al混合粉压坯试样进行烧结后,通过X射线衍射,扫描电镜及能谱分析,结果表明,球磨时间越长,越有利于Ti,Al之间的扩散反应,越容易形成Ti-Al金属间化合物,并有利于组织的均匀化。 相似文献
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Fabrication of ZrO2/AI203 green body through gelcasting process using low-toxicity monomer DMAA
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《复合材料学报》2012,29(1)
采用低毒的单体N,N-二甲基丙烯酰胺(DMAA)制备了氧化锆增韧氧化铝(ZrO2/A12O3)坯体。讨论了分散剂的用量、ZrO2/Al203浆料的pH值、粉体中Zr02含量、粉体所占浆料的固相体积分数、球磨时间、预混液中DMAA的浓度(质量分数)对ZrO2/Al203浆料黏度的影响。并研究了注凝成型ZrOz/Al203坯体的性能和显微结构。结果表明,当浆料pH值为9,分散剂的添加量为ZrO2/A1203粉体质量的0.6%,球磨时间为6h,ZrO2/Al203浆料具有最小的黏度。固相体积分数的提高和DMAA加入量的增大都会提高ZrO2/A12O3浆料的黏度,ZrOz的加入会降低浆料的黏度。用DMAA制备得到的ZrO2/Al203坯体结构均匀,抗弯强度达到25MPa。 相似文献
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Al-Fe alloys with Fe contents ranging from 5 to 12 wt% are produced by a double mechanical alloying process (DMA) which consists of a first step of mechanical alloying (MA1) applied to elemental Al and Fe powders, with subsequent heat treatment of MA1 powders to promote the formation of Al-Fe intermetallic phases, and a second mechanical alloying step (MA2) to refine the intermetallic phase, and consolidation of the produced powders by combination of degassing and hot extrusion. The effect of Fe content on the process, as well as on the mechanical properties of the extruded alloys, has been extensively studied. The alloys produced by this process show excellent tensile strength and stiffness at room and elevated temperatures due to the strengthening of Al by intermetallics, as well as to the stabilization of the structure by inert dispersoids. 相似文献
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Challipalli Suryanarayana Francis H. Froes 《Advanced materials (Deerfield Beach, Fla.)》1993,5(2):96-106
Application of mechanical alloying to titanium-base alloys is a recent development. A wide range of terminal phases and those based on titanium aluminides (both Ti3Al and TiAl) have been examined and it has been shown that synthesis of metallic phases can be achieved by mechanical alloying. The phases so synthesized include solid solutions, intermediate crystalline phases, amorphous phases, and nanostructured materials. It has also been shown that the resistance to coarsening of both the grains and the dispersoids in mechanically alloyed Ti3Al based alloys is much higher than in rapidly solidified alloys. The review concludes with some thoughts on future developments in this exciting area. 相似文献
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Rico MM Alcázar GA Zamora LE González C Greneche JM 《Journal of nanoscience and nanotechnology》2008,8(6):2858-2872
The effect of Mn and B on the magnetic and structural properties of nanostructured samples of the Fe60Al40 system, prepared by mechanical alloying, was studied by 57Fe M?ssbauer spectrometry, X-ray diffraction and magnetic measurements. In the case of the Fe(60-x)Mn(x)Al40 system, 24 h milling time is required to achieve the BCC ternary phase. Different magnetic structures are observed according to the temperature and the Mn content for alloys milled during 48 h: ferromagnetic, antiferromagnetic, spin-glass, reentrant spin-glass and superparamagnetic behavior. They result from the bond randomness behaviour induced by the atomic disorder introduced by the MA process and from the competitive interactions of the Fe-Fe ferromagnetic interactions and the Mn-Mn and Fe-Mn antiferromagnetic interactions and finally the presence of Al atoms acting as dilutors. When B is added in the Fe60Al40 alloy and milled for 12 and 24 hours, two crystalline phases were found: a prevailing FeAl BCC phase and a Fe2B phase type. In addition, one observes an additional contribution attributed to grain boundaries which increases when both milling time and boron composition increase. Finally Mn and B were added to samples of the Fe60Al40 system prepared by mechanical alloying during 12 and 24 hours. Mn content was fixed to 10 at.% and B content varied between 0 and 20 at.%, substituting Al. X-ray patterns show two crystalline phases, the ternary FeMnAl BCC phase, and a (Fe,Mn)2B phase type. The relative proportion of the last phase increases when the B content increases, in addition to changes of the grain size and the lattice parameter. Such behavior was observed for both milling periods. On the other hand, the magnetic hyperfine field distributions show that both phases exhibit chemical disorder, and that the contribution attributed to the grain boundaries is less important when the B content increases. Coercive field values of about 10(2) Oe slightly increase with boron content. Comparison with previous results on FeAIB alloys shows that Mn promotes the structural stability of the nanostructured powders. 相似文献
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N. García-Rodríguez M. Campos J. M. Torralba M. H. Berger Y. Bienvenu 《Materials Science & Technology》2014,30(13):1676-1684
AbstractOxide dispersion strengthened (ODS) Fe alloys were produced by mechanical alloying (MA) with the aim of developing a nanostructured powder. The milled powders were consolidated by spark plasma sintering (SPS). Two prealloyed high chromium stainless steels (Fe–14Cr–5Al–3W) and (Fe–20Cr–5Al+3W) with additions of Y2O3 and Ti powders are densified to evaluate the influence of the powder composition on mechanical properties. The microstructure was characterised by scanning electron microscope (SEM) and electron backscattering diffraction (EBSD) was used to analyse grain orientation, grain boundary geometries and distribution grain size. Transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) equipped with energy dispersive X-ray spectrometer (EDX) were used to observe the nanostructure of ODS alloys and especially to observe and analyse the nanoprecipitates. Vickers microhardness and tensile tests (in situ and ex situ) have been performed on the ODS alloys developed in this work. 相似文献
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Elemental powders of Fe and Al were mechanically alloyed using a high energy rate ball mill. A nanostructure disordered Fe(Al)
solid solution was formed at an early stage. After 28 h of milling, it was found that the Fe(Al) solid solution was transformed
into an ordered FeAl phase. During the entire ball milling process, the elemental phase co-existed with the alloyed phase.
Ball milling was performed under toluene to minimise atmospheric contamination. Ball milled powders were subsequently annealed
to induce more ordering. Phase transformation and structural changes during mechanical alloying (MEA) and subsequent annealing
were investigated by X-ray diffraction (XRD). Scanning electron microscope (SEM) was employed to examine the morphology of
the powders and to measure the powder particle size. Energy dispersive spectroscopy (EDS) was utilised to examine the composition
of mechanically alloyed powder particles. XRD and EDS were also employed to examine the atmospheric and milling media contamination.
Phase transformation at elevated temperatures was examined by differential scanning calorimeter (DSC). The crystallite size
obtained after 28 h of milling time was around 18 nm. Ordering was characterised by small reduction in crystallite size while
large reduction was observed during disordering. Micro hardness was influenced by Crystallite size and structural transformation. 相似文献
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The effects of Ti-substitution for Fe in the Fe3Al system on the mechanical alloying process were investigated. For this purpose, blended elemental powders with the following nominal compositions (at.%): Fe75Al25, Fe70Ti5Al25, Fe65Ti10Al25, Fe60Ti15Al25, were mechanically alloyed in a high energy attritor-type ball milling system for up to 100 h. The structural evolution in these powders was characterized by scanning electron microscopy, differential thermal analysis and X-ray diffraction techniques. It was found that elemental powders were progressively transformed into nanocrystalline solid solutions during mechanical alloying. The addition of Ti in the powders shortened the milling time for solid solution formation. With increasing Ti content, the grain size of the solid solutions decreased, but the lattice parameter increased. Upon heating, the milled powders were transformed into ordered (Fe,Ti)3Al intermetallic compounds in an extended range of temperature (from 350 to 500°C). Ti addition enhanced the occurrence of DO3 ordering in heated powders. 相似文献
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基于合金化的改性原理,以调整材料的长程有序度为改性思想,采用真空电弧熔炼/热压退火制备了四种Cr/Al复合合金化Fe3Si基有序合金。通过XRD,SEM,EPMA等对合金进行了表征,并采用长程有序参数定量表征了退火得到的有序相的有序程度。结果表明:四种不同成分的有序合金,具有不同的显微组织。随着Si含量降低合金有序度下降,且Cr/Al的复合效应对这一趋势起到了促进作用,使得具有相同Si含量的Fe65Si25Cr5Al5有序合金的有序度低于Fe3Si,分别为0.658和0.796。 相似文献