共查询到19条相似文献,搜索用时 108 毫秒
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磁控溅射沉积Cu-Nb薄膜的特征及热退火的影响 总被引:1,自引:0,他引:1
用磁控共溅射法制备含铌1.16%~27.04%(原子分数)的Cu-Nb合金薄膜,运用EDX,XRD,SEM,TEM,显微硬度仪和电阻仪对沉积态和热退火态薄膜的成分、结构和性能进行了研究.结果表明,Nb添加显著影响Cu-Nb合金薄膜微结构,使Cu-Nb薄膜晶粒细化,含铌1.82%~15.75%的Cu-Nb膜呈纳米晶结构,存在Nb在Cu中的fec Cu(Nb)非平衡亚稳过饱和同溶体,固溶度随薄膜Nb浓度增加而上升,最大值为8.33%Nb.随Nb含量增加,薄膜中微晶体尺寸减小,Cu-27.04%Nb膜微结构演变至非晶态.与纯Cu膜对比表明,Nb添加显著提高沉积态Cu-Nb薄膜显微硬度和电阻率,总体上二者随膜Nb含量上升而增高.Nb含量高于4.05%时显微硬度增幅趋缓,非晶Cu-Nb膜硬度低于晶态膜,电阻卒则随铌含量上升而持续增加.经200,400及650℃退火1h后,Cu-Nb膜显微硬度降低、电阻率下降,降幅与退火温度呈正相关.XRD和SEM显示,650℃退火后晶态Cu-Nb膜基体相发生晶粒长大,并出现亚微米级富Cu第二相,非晶Cu-27.04%Nb膜则观察到晶化转变和随后的晶粒生长.Nb添加引起晶粒细化效应以及退火中基体相晶粒度增大是Cu-Nb薄膜微观结构和性能形成及演变的主要原因. 相似文献
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采用磁控共溅射方法分别制备了含有W和Mo两种不同成分的铜系薄膜,用EDX、XRD、SEM和纳米压痕仪对薄膜成份、结构、形貌和显微硬度进行了分析。结果表明,制备出的Cu—W和Cu-Mo薄膜均呈晶态结构,Cu-W和Cu—Mo形成了均匀的固溶体;经650℃热处理1h后,Cu—W和Cu—Mo薄膜中晶粒长大,有富w和富Mo相从基体Cu相中弥散析出;Cu-W薄膜的显微硬度随W成分的增加先增加后降低;Cu—Mo薄膜的显微硬度随Mo成分的增加而持续升高,薄膜退火态的显微硬度低于沉积态。分析认为,以上结果的产生均因添加W、Mo所引起的晶粒细化效应和薄膜的热稳定性较差所致。 相似文献
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球磨法制备Mg-Cu非晶态合金粉末 总被引:1,自引:0,他引:1
本文研究了Mg—Cu二元相图的三个共晶点成分配方和两个化合物成分配方在球磨条件下非晶态合金的形成能力。XRD结果显示:除一个共晶点成分配方外,其它所有成分配方都能形成非晶态合金;非晶形成能力由大到小依次为MgCu2(化合物),Mg58Cu42(共晶点),Mg2Cu(化合物),Mg85Cu15(共晶点),Mg22Cu78(共晶点)。显然,作为选择非晶态合金成分的判据来说,Schwarz与Johnson的两个条件准则比Davies的共晶线准则更加合适。非晶形成的过程是:首先发生Mg在Cu中的固溶,随后形成过饱和固溶体,最后过饱和固溶体失稳形成非晶态合金。 相似文献
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用Zr,Al,Ni和Cu的元素粉末,采用机械合金化的方法在转速为400 r/min、球料质量比20:1的条件下制备具有非晶结构的Zr50Al15 Ni10Cu25粉末,研究其非晶化机制。用X射线衍和扫描电镜分析粉末的结构、晶粒尺寸和形貌。结果表明:在球磨8 h后可使Zr50Al15 Ni10Cu25混合粉末非晶化,晶粒尺寸约80 nm;球磨过程中并没有出现任何过饱和固溶体或者中间合金相,非晶化过程是由于球磨过程中球磨罐和磨球对粉末的不断冲击、剪切、摩擦和挤压,使混合粉末中的晶粒极度细化而直接转变为非晶态颗粒,得到非晶粉末。 相似文献
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对Laves相Cr2Nb化学配比成分的元素混合粉末的机械合金化行为进行了研究.结果表明,在机械合金化过程中,Cr、Nb元素混合粉末首先变成复合粉末,复合粉末中的成分逐渐均匀并演变成过饱和固溶体.机械合金化40h后过饱和固溶体发生部分非晶化.粉末颗粒尺寸在机械合金化初期的5h内粗化,随后逐渐细化,50h后细至亚微米级.在50h的机械合金化过程中始终未发现Laves相Cr2Nb的合成.但15h的机械合金化粉末在900℃的较低温度下通过固相热反应合成出了Laves相Cr2Nb,而未球磨的原始粉末在此温度下未能合成.这说明机械合金化虽然没有直接合成出Laves相Cr2Nb,但产生了活化Laves相高温反应合成的效果,使合成反应温度显著降低. 相似文献
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B. N. Mondal A. Basu Mallick D. N. Nath P. P. Chattopadhyay 《Metallurgical and Materials Transactions A》2011,42(2):517-523
An attempt was made to study the effect of Mn addition on the formation of supersaturated solid solution of Co and Fe in Cu
during ball milling and precipitation of the solute-rich phases during subsequent annealing of the ball-milled product. It
is demonstrated that the addition of Mn in the ternary CuFeCo powder blend enhances the metastable solubility of Fe and Co
in Cu and facilitates the formation of the nanocrystalline supersaturated single-phase solid solution. Field emission–scanning
electron microscopy (FE-SEM) also revealed notable influence of Mn on the morphological evolution of the ball-milled and annealed
alloy powders. X-ray diffraction (XRD) analysis revealed that the FeCo phase having the bcc Bravais lattice forms after annealing
at and above 620 K (350 °C) in both alloys. Estimation of magnetic properties showed that Mn addition in the CuFeCo alloy
improved the coercivity, remanence, and magnetic saturation. 相似文献
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HREM and FEG TEM were emphasized and extensively used to follow the most subtle changes in the structure and composition of ball-milled Cu, Fe-Cu, and thermally decomposed Fe60Cu40. Some significant results are obtained and summarized as follows: HREM shows that the deformation of ball-milled copper proceeds mainly by twinning and shear bands (SBs) formation. The nano-grains formed during ball milling (BM) contain a high density of dislocations. The grain boundaries (GBs) of nanocrystalline (NC) Cu prepared by BM are ordered, curved, and strained, but disordering, lattice distortion, and nanovoids in local regions were frequently observed. Nanoscale composition analysis on mechanically alloyed Fe16Cu84 shows that the average Fe content in both the interior of grains and the GBs is close to the designed composition, which proves that a supersaturated solid solution has really formed. However, the Fe content is rather inhomogeneous between the larger and smaller grains, which infers the inhomogeneous mixing of Fe and Cu during mechanical alloying (MA). NC structure and the mechanical force-enhanced fast diffusion are the reasons of the formation of supersaturated solid solutions in immiscible systems with positive enthalpy of mixing. HREM observations carried out with the thermally decomposed Fe60Cu40 solid solution show that the Nishiyama (N-W) or Kurdyumov-Sachs (K-S) orientation relationships exist between alpha-Fe and Cu. Energy dispersive X-ray spectra (EDXS) results show that the Cu content in these alpha-Fe grains reaches as high as 9.5 at.% even after heating to 1,400 degrees C, which is even higher than the maximum solubility of Cu in gamma-Fe at 1,094 degrees C. 相似文献
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L. L. Rokhlin S. V. Dobatkin T. V. Dobatkina N. I. Nikitina I. E. Tarytina E. V. Tat’yanin M. V. Popov 《Russian Metallurgy (Metally)》2006,(1):80-85
The effect of severe plastic deformation by high-pressure torsion on the structure and properties of aged magnesium alloys containing 2.8–5.5 wt % Sm (the maximum solubility of samarium in solid magnesium is 5.8 wt %) are studied. The severe plastic deformation leads to substantial strengthening caused by the formation of a submicrocrystalline structure along with strengthening caused by the decomposition of a supersaturated magnesium-based solid solution. 相似文献
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Two Al-rich Al-Ta alloys containing by weight 3 and 6 pct Ta have been rapidly solidified from the melt using the ‘gun’ technique.
The microstructures and the crystal structures of the phases in the as-solidified as well as those formed on subsequent decomposition
of the supersaturated solid solution have been characterized. A supersaturated solid solution was obtained in both the alloys
in the as-solidified condition indicating a solid solubility extension of Ta in Al to almost 6 wt pct. The supersaturated
solid solutions formed in both the alloys have been found to be quite stable up to 673 K (for 1 hour). Annealing at higher
temperatures resulted in the formation of rod-shaped precipitates inside the grains and massive precipitates along grain boundaries.
The rod-shaped precipitates arranged in a regular pattern constitute a new metastable intermediate phase Al7Ta having an ordered structure. The massive precipitates which form along grain boundaries constitute the equilibrium Al3Ta phase with a tetragonal crystal structure. The transformation behavior and the morphology of the transformation products
are detailed in this paper. 相似文献
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H. F. Rizzo T. B. Massalski M. Nastasi 《Metallurgical and Materials Transactions A》1993,24(5):1027-1037
The possibility of producing nonequilibrium amorphous and crystalline phases in the Cu-W system is of interest because, under equilibrium conditions, no mutual solubility is expected between Cu and W. Triode sputtered coatings (45 to 150 μm thick, produced at deposition rates between 20 and 150 Å/s) consisted of amorphous and metastable crystalline phases. The latter remained decomposition-resistant on heating to various temperatures between 340 °C and 600 °C (the maximum temperature of exposure). The amorphous phase in such coatings crystallized on heating into a metastable body-centered cubic (bcc) phase, and the crystallization temperatureT x was found to decrease across the phase diagram from 450 °C to 340 °C as the percentage of W increased from 26 to 60 at. pct. Samples containing amorphous phase regions, when subjected to heating between 150 °C and 250 °C, showed an unusual rapid precipitation of Cu at the sample surface, indicating an easy diffusion of the Cu component. This occurred without crystallization of the remaining slightly tungsten-enriched amorphous matrix. Microhardness measurements in sputtered two-phase amorphous and bcc regions have shown that in alloys of the same composition, the amorphous phase was always softer than the bcc solid solution phase. X-ray, microprobe, and optical evidence suggests that the amorphous films deposited at very low temperatures(i.e., at liquid N2) may subsequently undergo a phase separation upon heating to room temperature and prior to crystallization. Earlier work and present studies of vapordeposited alloys in this system confirm that the observed phases and microstructures can be related to free energy trends estimated from thermodynamic considerations and to specific deposition parameters, such as the substrate temperature and the deposition rates, which influence the kinetics. 相似文献
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H. F. Rizzo T. B. Massalski E. D. McClanahan 《Metallurgical and Materials Transactions A》1988,19(1):5-12
The triode sputtering technique and a split Cu-Ti target arrangement have been used to produce metastable extended solid solutions
and amorphous phases in the Cu-Ti system. Metastable extension of the solid solubility of Ti in Cu-based fcc solid solution
of up to 30 at. pct was observed; nearly 20 at. pct of Cu was incorporated metastably into the hcp solid solution based on
Ti. Amorphous phase formation was observed in alloys containing approximately between 26 and 84 at. pct Ti. Amorphous deposits
were as thick as 250 μm, without the presence of detectable crystalline phases. Interatomic spacings in both crystalline and
amorphous alloys were found to follow an approximately linear trend with composition. Microhardness measurements indicated
a very substantial increase in hardness in all alloys when compared with an extrapolated linear trend between pure Cu and
Ti. 相似文献
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《粉末冶金学》2013,56(29):1-10
AbstractThe binder phase of WC-Co cemented carbide is a Co-rich alloy in which tungsten and carbon are in solid solution. The binder phase is supersaturated with respect to tungsten even after slow cooling from the sintering temperature. In this study the binder phase contained 6% W in solid solution before heat-treatment at 650°C (923 K). Transmission electron microscopy on thin foils of binder phase showed that a finely dispersed. phase, α′, precipitated in the cubic binder phase. After long ageing times Co3W could be identified by X-ray diffraction methods. As no discontinuous , ‘cells’ of Co3W and ?-Co could be observed, the following reaction is suggested.α-Co(W, C)→α-Co+α′→α-Co (C)+Co3W (needles)The precipitation of α′ was accompanied by an increase in hardness and a decrease in transverse rupture strength. The effects observed are consistent with those found during annealing of Co-rich cobalt-tungsten-carbon alloys (> 85% Co). 相似文献
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The bulk Al–Cu-multiwall carbon nanotube (MWCNT) nanocomposite was prepared using mechanical alloying (MA) and hot extrusion processes. Al–4 wt % Cu powder mixture was first milled for 20 h to form the nanostructured Al(Cu) solid solution. The MWCNT was then added to the Al(Cu) powder mixture and further milled for 5 h. X-Ray Diffraction (XRD) and Differential Thermal Analysis (DTA) were performed to study the phase transformations during mechanical alloying and hot extrusion. Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) were also employed to study the samples microstructure. Mechanical properties of the bulk Al(Cu)/CNT nanocomposite were also studied using room and high temperature compression and wear tests. The results showed that after 20 h of mechanical alloying, a supersaturated Al(Cu) solid solution with the average grain size of 25 nm was achieved. Homogenous distribution of CNTs in the Al(Cu) supersaturated matrix was obtained. CNTs retained their tubular structure after 5 h milling time. Hot extrusion process at 550°C also led to the formation of bulk samples with nearly full density. The average yield and compressive strength of the Al(Cu)/CNT nanocomposite were found to be around 450 and 590 MPa at room temperature. The bulk nanocomposite showed suitable thermal stability by keeping its strength up to 300°C. 相似文献