机械合金化制备铜碳过饱和固溶体

采用机械合金化方法制备Cu-4wt%C过饱和固溶体,通过SEM和XRD分析研究了机械合金化中Cu-C复合粉末的形貌变化及碳在铜中的固溶度扩展问题.结果表明,机械合金化过程中Cu粉和C粉形成了层状复合粉末;随着球磨时间的增加,C的衍射峰逐渐消失,Cu的衍射峰逐渐宽化,并且位置发生偏移;球磨24h后,C原子固溶到Cu中,Cu的点阵常数达到0.3620nm,晶格膨胀了0.15%.     

机械合金化W-Ni-Fe纳米复合粉的制备及结构研究

W,Ni,Fe粉末按照91.16W6．56Ni2.26Fe和95W5Ni的成分配比进行了机械合金化(MA)．通过调整球磨转速、球磨时间等工艺参数研究了其对粉末结构的影响,并对机械合金化粉末的物相、合金化特性、晶粒尺寸、点阵畸变及粉末形貌和颗粒度作了测定和分析讨论.机械合金化使晶粒细化并产生孪晶和位错．有利于原子扩散形成过饱和固溶体和非晶；高的球磨能有利于形成非晶相、晶粒细化和点阵畸变，350r／min球磨20h后晶粒尺寸可达25nm；输入的球磨能不同．粉末粒度的变化路径不同，但都会经历长大，变小和稳定三个不同阶段.     

机械合金化制备纳米晶Ti-6Al-4V合金

采用机械合金化制备Ti-6Al-4V粉末。结果表明:采用机械合金化可以制备纳米晶Ti-6Al-4V合金粉,其反应机理以扩散为主,该固态反应是缺陷能和碰撞能共同作用的结果;随球磨时间延长,部分V固溶于Ti中形成置换固溶体Ti(V),球磨过程中没有中间相生成。球磨40 h后都能获得纳米晶,60 h的粉末为纳米晶和非晶的混合物,晶粒尺寸小于60 nm;60 h后晶粒尺寸变化缓慢。球磨后Ti、Al、V的原子比近似为90:6:4,与Ti-6Al-4V元素成分一致。     

Cu-Cr-Zr复合粉末机械合金化研究

以Cu、Cr和Zr粉末为原料,采用机械合金化制备了Cu-90%Cr2Zr复合粉末。利用X射线衍射仪(XRD)和扫描电镜(SEM)研究了机械合金化过程中粉末的物相和微观形貌。结果表明:Cu-Cr-Zr粉末可通过机械合金化获得过饱和固溶体;在一定的球磨时间内,随球磨的进行,Cu-Cr-Zr粉末晶粒细化至纳米尺寸,晶格常数增加,晶格畸变降低,粉末形貌呈片状;但进一步球磨会导致铬的晶格常数降低,导致畸变增加,使得粉末变得不规则及颗粒大小不均。     

机械合金化对Cr-W粉末及烧结材料组织的影响

通过机械球磨法制备原子比为4:1的Cr-W预合金粉末,对球磨后的Cr-W粉末进行XRD、SEM、TEM分析,探讨球磨时间对Cr-W粉末形貌、晶粒大小、组织结构及烧结Cr-W合金固溶度的影响。结果表明：采用机械合金化法,可以制备纳米级的Cr-W预合金粉末;球磨初期,晶粒尺寸、微应变变化较大,48 h后趋于稳定获得小于30 nm的纳米晶粉末;经72 h球磨后,粉末中有固溶体形成;球磨过程伴随着晶格常数的变化;球磨时间越长的粉末,烧结后各相分布越均匀,固溶程度越高     

机械合金化过程中Fe-Al合金粉末的组织演变

将纯Fe粉和Al粉按原子比Fe∶Al=60∶40混合后,在行星式高能球磨机中进行机械合金化,采用X射线衍射仪、扫描电镜、透射电镜和硬度仪研究球磨过程中Fe-Al合金粉末相结构、晶粒尺寸、表面形貌、截面形貌和硬度的演变规律。结果发现,球磨24 h后,Al原子全部固溶于Fe晶格中,形成Fe(Al)过饱和固溶体,随着球磨时间的增加,晶粒尺寸呈现先快后慢的减小趋势,球磨36 h后合金粉末的晶粒尺寸小于100 nm。粉末内部组织为层状结构,且随着球磨时间延长层片厚度不断减小,球磨36 h后层状结构全部消失,获得组织均匀的纳米晶Fe-Al合金粉末。随着球磨时间延长,Fe-Al合金粉末的硬度不断增加,球磨36 h后合金粉末的硬度约为405 HV0. 025。球磨Fe(Al)固溶体合金粉末在500℃热处理转变为有序Fe Al金属间化合物。     

机械合金化制备Ta-10%Al纳米晶过饱和固溶体

利用机械合金化的方式制备了组成为Ta-10%Al(质量比)的纳米晶过饱和固溶体。以XRD和SEM为表征手段,研究了球磨时间对Ta-10%Al纳米晶过饱和固溶体产生的影响,并对Ta-10%Al纳米晶过饱和固溶体形成的热力学机理进行了研究。结果表明,随球磨时间增加,Al逐渐溶入Ta中。当球磨时间达到48 h后,Al完全固溶进Ta中形成Ta-10%Al纳米晶过饱和固溶体,晶粒尺寸和微观应力分别为84.3 nm和0.285%。延长球磨时间导致Ta-10%Al纳米晶过饱和固溶体晶粒细化且微观应力增加,过长的球磨时间可能引发合金粉末的团聚。以Miedema半经验模型为依据,建立了机械合金化过程中的热力学模型,计算结果显示,以机械合金化为手段制备Ta-10%Al纳米晶过饱和固溶体的主要驱动力来源于热力学驱动。     

Ni50Mn43Sn7磁性形状记忆合金的机械合金化及其磁性能（英文）

利用机械合金化法制备Ni50Mn43Sn7磁性形状记忆合金粉末。采用X射线衍射(XRD)、扫描电镜(SEM)及振动样品磁强计(VSM)等分析手段研究了机械合金粉末的微观结构和磁性随球磨时间的变化。结果表明:在球磨过程中,依次形成一些Mn1.77Sn,MnSn2,Ni3Sn4,Ni3Sn2和Ni4Sn等中间相,随着球磨时间的增加,MnSn化合物与NiSn化合物逐渐结合而消失,球磨270h后,形成Ni2MnSn,机械合金化完成。在球磨初期,粉末晶粒尺寸急剧减小,球磨90h后晶粒尺寸基本保持稳定,颗粒以絮状团聚结构存在。由于球磨过程中粉末得到细化等原因,饱和磁化强度Ms随球磨时间的增加而减少,矫顽力(Hc)随球磨时间的增加先增大,球磨90h后急剧减小。     

机械合金化法制备Cu-Nb合金过程中的形变孪生特性

采用机械合金化法制备纳米Cu-10%Nb合金,通过显微硬度测量以及高分辨透射电镜观察,对该合金粉末在室温球磨过程中的微观结构演变和形变孪生特性进行研究;利用局部应力集中模型分析形变孪晶的形核机制。结果表明:随着球磨时间的增加,该合金硬度(HV)不断升高,球磨120 h后可达4.8 GPa;该合金在球磨初期以位错胞结构为主;球磨50 h后,Cu平均晶粒尺寸减小至约50 nm,部分区域出现纳米形变孪晶;继续增加球磨时间,孪晶数量增加,孪晶界强化效果显著;由于孪生将促进纳米晶粒的进一步细化,球磨120 h后,纳米晶尺寸减小到20 nm以下。     

机械合金化制备Al_(65)Fe_(25)Ni_(10)纳米合金粉的磁性研究

用机械合金化法制备A165Fe25Ni10纳米合金粉末.采用X射线衍射(XRD)、振动样品磁强计(VSM)研究了其结构和磁性随球磨时间的演变.结果表明:在球磨初期,粉末晶粒尺寸急剧减小,内应变迅速增大:球磨50 h后晶粒尺寸、内应变基本保持稳定.矫顽力(Hc)随球磨时间的增加先增大,球磨50 h后急剧减小.在晶粒尺寸较小时,矫顽力与晶粒尺寸的六次方成正比;晶粒尺寸较大时,矫顽力与晶粒尺寸成反比.     

Cu-15wt%Cr复合粉末机械合金化及稀土掺杂研究

以Cu、Cr和稀土粉末为原料,采用机械合金化法制备Cu-15wt%Cr和Cu-15wt%Cr-RE复合粉末.利用X射线衍射仪、扫描电镜研究了球磨过程粉末的显微组织结构,测量不同球磨时间粉末的显微硬度.结果表明:随着球磨时间的延长,Cr在Cu中的固溶度显著提高,晶粒不断细化和微应变增加,导致粉末微观硬度的提高.在球磨过程中添加一定量的稀土可以促进机械合金化效果.     

机械合金化对W-20Cu复合材料的显微组织与性能的影响

采用机械合金化结合粉末冶金技术制备W-20Cu（vo1％）复合材料。利用扫描电镜和金相显微镜对不同球磨时间的W-20Cu复合材料显微组织进行表征，并对材料的各项物理性能进行测试。结果表明，随着球磨时间的延长，W-20Cu烧结体的组织越来越均匀，Cu相分布也越来越均匀。W-20Cu烧结体密度、收缩率、硬度、抗弯强度随球磨时间的延长而增大；球磨20h的W-20Cu复合粉烧结体热导率达到峰值（130．61Wm^-1K^-1），继续球磨，热导率减小。综合考虑所有研究结果，通过机械合金化所制备的W-Cu复合粉体可以获得具有优异综合物理性能的W-20Cu复合材料。     

Mechanically induced crystalline–glassy phase transformations of mechanically alloyed Ta55Zr10Al10Ni10Cu15 multicomponent alloy powders

New multicomponent Ta-based glassy alloy powder was synthesized by mechanical alloying (MA) the elemental powders of Ta₅₅Zr₁₀Ni₁₀Al₁₀Cu₁₅ at room temperature, using a low-energy ball milling technique. During the early stage of milling the agglomerated crystalline powders are mechanically crushed and fresh surfaces are rapidly created. Kneading of such ground powders enhances the atomic diffusion and leads to local alloying. As the MA time increases, the number of vacancies in the Ta lattice (base material) increases so that the atoms of the alloying elements for Zr, Al, Ni and Cu tend to migrate to the open defected lattice of metallic Ta. The number of atoms of the alloying elements that migrate to the bcc lattice of the base material are increasing with increasing MA time and this leads to a monotonic expansion of the Ta lattice. Further milling time (86–130 ks) plays an important role in increasing the rate of diffusion and this leads to an increase in the number of migrated atoms of the alloying elements that pass into the Ta lattice. The a₀ of the yielded solid solution at this stage does not change anymore with increasing MA time and a homogeneous supersaturated bcc-solid solution is obtained after 130 ks of MA time. This solid solution, which is subjected to continuous imperfections, is gradually transformed into a glassy phase upon increasing the MA time. The glassy powders of the final-product (1080 ks) in which its glass transition temperature (T_g) lies at a high temperature (834 K), crystallize through a single sharp exothermic peak at 1004 K (T_x). The total enthalpy change of crystallization (ΔH_x) is −10.32 kJ/mol. The width of the supercooled liquid region before crystallization (ΔT_x) of the synthesized glassy powder shows the largest value (170 K) of any reported metallic glassy system.     

高能球磨制备Al-Pb-Si-Sn-Cu纳米晶粉末的特性

通过机械合金化制备了Al-15％Pb-4％Si-1％Sn-1．5％Cu(质量分数)纳米晶粉末。采用X射线衍射(XRD)，扫描电镜(SEM)和透射电镜(TEM)对不同球磨时间的混合粉末的组织结构、晶粒大小、微观形貌以及颗粒中化学成分分布情况进行了研究。结果表明混合粉末经过球磨后形成了纳米晶，其组织非常均匀。球磨对Pb的作用效果明显大于对Al的作用效果，经过40h球磨后Pb粒子达到40nm，而Al在球磨60h后晶粒为65nm；经球磨后，Cu和Si固溶于Al的晶格中，而Sn则固溶于Pb晶格中，并且Al和Pb发生了互溶，形成了Pb(Al）超饱和固溶体；在球磨过程中硬度高的脆性粒子Si难于完全实现合金化。     

不同组分Cu-Cr、Cu-Mo机械合金化相演变特征

采用X射线衍射(XRD)仪与透射电镜(TEM)选区电子衍射(SAED)对不同组分Cu-Cr、Cu-Mo高能球磨粉末在机械合金化过程中的相演变特征进行了研究,Mo在Cu中以晶格固溶为主,通过机械合金化手段扩展Mo在Cu中的固溶度有限,随着Mo组分含量增加,Cu晶粒尺寸变小,Mo在Cu中固溶度增大,Cu-80%Mo球磨产物中有非晶相出现。Cr在Cu中的固溶以晶界亚互溶为主,球磨强度影响Cu-50%Cr(质量分数)合金化产物,较高球磨强度下生成Cu纳米晶与Cr的氧化物。     

Mechanical alloying behavior of Nb–Ti–Si-based alloy made from elemental powders by ball milling process

Nb-Ti-Si-based alloy powders were prepared by mechanical alloying(MA) of elemental particles.The evolutions of morphology,size,phase constituents,crystallite size,lattice strain,composition and internal microstructure,etc.,of the alloy powders were analyzed by X-ray diffraction(XRD),scanning electron microscopy(SEM),energy-dispersive spectroscopy(EDS),laser particle size analyzer and transmission electron microscope(TEM) analyses.The alloy particles are gradually refined and their shapes become globular with the increase in milling time.The diffraction peaks of Nb solid solution(Nbss) phase shift toward lower29 angles during ball milling from 2 to 5 h,and after that Nbss diffraction peaks shift toward higher 29 angles with the increase in milling time from 5 to 70 h,which is mainly attributed to the alteration of the lattice parameter of Nbss powders due to the solution of the alloying element atoms into Nb lattice to form Nbss.During ball milling process,the decrease in crystallite size and increase in lattice strain of Nbss powders lead to continuous broadening of their diffraction peaks.A typical lamellar microstructure is formed inside the powder particles after ball milling for 5 h and becomes more refined and homogenized with the increase in milling time.After 40-h-ball milling,the typical lamellar microstructure disappears and a very homogeneous microstructure is formed instead.This homogeneous microstructure is proved to be composed of only supersaturated Nbss phase.     

Microstructure and properties of copper composite containing in situ NbC reinforcement: Effects of milling speed

This paper presents a study on the effects of milling speed on the properties of in situ copper-based composite produced by mechanical alloying followed by cold pressing and sintering. A powdered mixture of copper, niobium and graphite with the composition of Cu–30%NbC was milled at various speeds (100, 200, 300 and 400 rpm). The NbC phase started to precipitate in the as-milled powder after 30 h milling at 400 rpm and the formation was completed after sintering at 950 °C. Enhancements of NbC phase formation with a reduction in Cu crystallite size were observed with the increase of milling speed. Density, hardness and electrical conductivity of the sintered composite were evaluated. An increase in milling speed resulted in an increase in sintered density and hardness but a reduction of electrical conductivity. The changes in the properties were correlated to the formation of NbC phase and refinement of copper and niobium carbide crystallite size since higher milling speed is associated with higher kinetic energy per hit.