Effect of Annealing Conditions on the Grain Size of Nanocrystalline Copper Thin Films

2008 ◽  
Vol 587-588 ◽  
pp. 483-487 ◽  
Author(s):  
Sonia Simões ◽  
Rosa Calinas ◽  
P.J. Ferreira ◽  
M. Teresa Vieira ◽  
Filomena Viana ◽  
...  
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Grain Size ◽  
Grain Growth ◽  
Copper Substrate ◽  
Nanocrystalline Metals ◽  
Nanocrystalline Copper ◽  
Annealing Conditions ◽  
Transmission Electron ◽  
Average Grain Size

Nanocrystalline metals demonstrate a broad range of fascinating mechanical properties at the nanoscale, namely a significant increase in hardness and superior yield stress. In this regard, understanding grain growth in nanocrystalline metals is crucial, particularly because nano size grains are characterized by a high curvature, which results in a high driving force for grain growth. In this work, the effect of annealing conditions on grain size of copper nanocrystalline thin films was investigated. The nanocrystalline copper thin films were first deposited by d.c. magnetron sputtering on a copper substrate. The specimens were then annealed in vacuum at 100, 300 and 500°C from 10 minutes to 5 hours. Transmission electron microscopy observations revealed that the as-deposited thin films have a bimodal grain size distribution; an average grain size of 43±2nm and the presence of nanotwins. Abnormal grain growth was observed for some samples annealed. Increasing the annealing time induced significant grain growth and promoted twin formation in the larger grains. Finally, the hardness of these nanocrystalline Cu thin films was determined using atomic force microscope. The relation between mechanical properties, annealing conditions and grain size was analyzed.

Texture Evolution of Lithium Fluoride Thin Films by Nucleation

2006 ◽  
Vol 979 ◽  
Author(s):  
Hakkwan Kim ◽  
Alexander H. King
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Substrate Temperature ◽  
Lithium Fluoride ◽  
Texture Evolution ◽  
Dark Field ◽  
Acceptable Error ◽  
Annealing Conditions ◽  
Surface Normal ◽  
Transmission Electron

AbstractWe have used a transmission electron microscope (TEM)-based method to extract grain size information for 〈111〉 surface normal grains in lithium fluoride (LiF) thin films, and applied this to analyze textures as a function of substrate temperature and annealing time. The size distributions of grains diffracting into the (111)+(200) and (220) rings were measured separately using dark field (DF) TEM images. From these data, we deduce the distribution of 〈111〉 surface normal grain sizes based on the assumption that only 3 principal textures (100), (110) and (111) exist in films. The (111) texture formation was also observed by x-ray diffraction (XRD). For all deposition and annealing conditions, the grain size data can be matched to lognormal distributions within an acceptable error, but at longer annealing times the distribution becomes bimodal. A novel feature of the LiF films is that the (111) texture component strengthens with annealing and substrate temperature, through the nucleation of new grains rather than the growth of existing ones.

Ion Induced Grain Growth in Pd

1991 ◽  
Vol 235 ◽  
Author(s):  
D. A. Lilienfeld ◽  
P. Bøorgesen ◽  
P. Meyer
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Grain Growth ◽  
Low Temperatures ◽  
Nanocrystalline Materials ◽  
Ion Irradiation ◽  
Size Distributions ◽  
Careful Choice ◽  
Average Grain Size

ABSTRACTIon irradiation induced grain growth size distributions in Pd are examined at low temperatures. Two features are observed: 1) A majority of the grains saturate in size. 2) Some grains achieve sizes much larger than the average grain size and continue to grow with ion dose. However, by careful choice of ion mass and ion dose, it is possible to produce a sample possessing a monomodal grain size. This process will have applications in producing thin films of nanocrystalline materials.

Influence of Grain Size on Mechanical Properties in a Fe-9Ni-12Mn-2.5Si-1.0C TWIP Steel

2011 ◽  
Vol 197-198 ◽  
pp. 655-661
Author(s):  
Ze Bin Yang ◽  
Ding Yi Zhu ◽  
Wei Fa Yi ◽  
Shu Mei Lin ◽  
Cheng Mei Du
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Strain Hardening ◽  
Twip Steel ◽  
Optical Microscope ◽  
Coarse Grained ◽  
Microstructure Observation ◽  
Transmission Electron ◽  
Average Grain Size

We investigate the influence of grain size on mechanical properties in a Fe-9Ni-12Mn-2.5Si-1.0C TWIP steel by unidirectional tensile. Meanwhile the microstructures of the TWIP steel were observed and analyzed by optical microscope (OM) and transmission electron microscope (TEM). The experimental results show that the TWIP steel’s yield strength and tensile strength decrease with the increasing of grain size, whereas the plasticity increases with it. When the average grain size reaches to 27μm, the tensile strength is 1080MPa, the elongation percentage is 77%, and the strength-plasticity product achieves the 83160MPa•%. Steel’s strain hardening rate can be changed from three-stage to four-stage with the increasing of grain sizes, the areas of strain hardening by twin deformation mechanism are expanded. Through the microstructure observation we found that, coarse-grained TWIP steel conducts to twinning formation, the high density twins can increase the alloy’s ductility by splitting the grain.

Mechanical Properties of ECAE Nanocrystalline Copper and Nickel

2005 ◽  
Vol 23 ◽  
pp. 183-186 ◽  
Author(s):  
S. Bansal ◽  
A.M. Saxena ◽  
T. Hartwig ◽  
Rao R. Tummala
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Size ◽  
Tensile Strength ◽  
High Purity ◽  
Bulk Sample ◽  
Nanocrystalline Copper ◽  
Average Grain Size ◽  
Angular Extrusion ◽  
Bulk Nanocrystalline

Bulk nanocrystalline copper and nickel (average grain size ~ 50 nm) with high purity and density were synthesized by equichannel angular extrusion (ECAE). Both nanohardness and microhardness measurements revealed a significant increase in hardness of the bulk sample. The tensile strength of these materials has been found to be 5-6 times higher than conventional forms and our experiments show that Cu is extremely stable up to temperatures of 100 oC and Ni to temperatures of 250 oC. The fracture toughness, measured by the value of JIC for nc-copper and nickel have been found to be 21.66 KJ/m2 and 12.13 KJ/m2, respectively which are high for these strength levels.

Dielectric and microstructural properties of barium titanate zirconate thin films on copper substrates

2005 ◽  
Vol 20 (10) ◽  
pp. 2838-2844 ◽  
Author(s):  
J.F. Ihlefeld ◽  
J-P. Maria ◽  
W. Borland
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Barium Titanate ◽  
Room Temperature ◽  
Metallic Copper ◽  
Copper Substrate ◽  
Hydrogen Gas ◽  
Average Grain Size ◽  
Reductive Atmosphere ◽  
Unit Cell Dimensions

Barium titanate zirconate, Ba(Ti1−xZrx)O3 (0 ≤ x ≤ 0.25), thin films were deposited via the chemical solution deposition (CSD) method directly on copper foils. The films were processed in a reductive atmosphere containing nitrogen, water vapor, and hydrogen gas at 900 °C to preserve the metallic copper substrate during crystallization. Increasing the fraction of BaZrO3 revealed several effects, including an increase in unit cell dimensions, a decrease in both the temperature and value of the maximum permittivity, as well as a decrease in the average grain size of the films. The decrease in the relative permittivity was attributed to a grain size effect as opposed to zirconium substitution. In film compositions containing 25 mol% BaZrO3, the permittivity below Tmax became dispersive, and the ferroelectric transitions became increasingly diffuse. These characteristics suggest relaxor-like behavior. The dielectric tunability of Ba(Ti1−xZrx)O3 was studied at room temperature and at Tmax for each composition. There was little variation in the tunability with measurement temperature; however compositions that were ferroelectric at room temperature saw a decrease in hysteresis at Tmax, and all compositions showed an increase in permittivity.

Relaxation and Grain Growth Behavior of Nanocrystalline Iron

1992 ◽  
Vol 272 ◽  
Author(s):  
J. C. Holzer ◽  
R. Birringer ◽  
J. Eckert ◽  
C.E. Krill ◽  
W.L. Johnson
Keyword(s):  
Grain Size ◽  
Grain Growth ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Peak Broadening ◽  
Transmission Electron ◽  
Average Grain Size ◽  
Nanocrystalline Iron ◽  
Grain Growth Behavior ◽  
Kinetics Of

ABSTRACTNanocrystalline Fe has been prepared by inert gas condensation and ball milling. The kinetics of relaxation and grain growth are investigated by differential scanning calorimetry. The development of the microstructure is monitored by x-ray powder diffraction and transmission electron microscopy. Emphasis is placed on the differences observed for samples prepared by the two different techniques. We find that the kinetics of relaxation and grain growth are very sensitive to the sample preparation method. Samples with the same initial average grain size, as determined by the peak broadening in x-ray diffraction, show very different recovery behavior. The differences are discussed in terms of the estimated grain boundary energies and the initial grain size distribution obtained by the two preparation techniques.

The instability of polycrystalline thin films: Experiment and theory

1990 ◽  
Vol 5 (1) ◽  
pp. 151-160 ◽  
Author(s):  
K. T. Miller ◽  
F. F. Lange ◽  
D. B. Marshall
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Film Thickness ◽  
Grain Growth ◽  
Spherical Surface ◽  
Polycrystalline Film ◽  
Yttrium Nitrate ◽  
Zirconium Acetate ◽  
Polycrystalline Thin Films ◽  
Average Grain Size

Dense polycrystalline thin films of ZrO2 (3 and 8 mol % Y2O3) were produced by the pyrolysis of zirconium acetate precursor films, which were deposited on single crystal Al2O3 substrates by spin-coating aqueous solutions of zirconium acetate and yttrium nitrate. Dense films were heat treated to encourage grain growth. With grain growth, these films broke into islands of ZrO2 grains. Identical areas were examined after each heat treatment to determine the mechanism that causes the polycrystalline film to uncover the substrate. Two mechanisms were detailed: (a) for a composition which inhibited grain growth and produced a polycrystalline film with very small grains, the smallest grains would disappear to uncover the substrate, and (b) for a composition which did not inhibit grain boundary motion, larger grains grew by enveloping a smaller grain and then developed more spherical surface morphologies, uncovering the substrate at three grain junctions. In both cases, the breakup phenomenon occurred when the average grain size was larger than the film thickness. Thermodynamic calculations show that this breakup lowers the free energy of the system when the grain-size-to-film-thickness ratio exceeds a critical value. These calculations also predict the conditions needed for polycrystalline thin film stability.

Grain Growth in Al-(Cu, Pd, Nb) Thin Films

1993 ◽  
Vol 309 ◽  
Author(s):  
J.D. Mis ◽  
K.P. Rodbell
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Grain Growth ◽  
Weight Percent ◽  
Size Distributions ◽  
Precipitate Morphology ◽  
X Ray ◽  
Transmission Electron ◽  
Grain Size Distributions

AbstractThe microstructure of 1 μim thick Al films containing 0.5 and 2%Cu (weight percent), 0.3%Pd, and 0.3%Pd-0.3%Nb were investigated by transmission electron microscopy (TEM) and energy dispersive x-ray spectroscopy (EDS) as a function of isochronal and isothermal anneals. The grain size, grain size distribution, and precipitate morphology of these films was measured from 200 to 500ºC, with the activation energy for grain growth (Ea) determined for I h anneals at 200, 300, 400 and 500ºC. Normal grain growth was recorded for the A1Cu films annealed at temperatures ≤400ºC; however secondary grain growth occurred in the AI-2Cu film annealed for I h at 500ºC, with grains as large as 16 μm in diameter observed. Grain growth in the AI-0.3Pd films resulted in strongly bi-modal grain size distributions, with the onset ofsignificant grain growth retarded for I h anneals at temperatures ≤300ºC.The addition of Nb to the AI-0.3Pd film resulted in monomodal grain size distributions over the entire temperature range. The role of crystallographic texture on grain growth in thin films is discussed.

Dopant Diffusion and Grain Growth in Arsenic-Implanted Poly-Si

1987 ◽  
Vol 106 ◽  
Author(s):  
L. R. Zheng ◽  
L. S. Hung ◽  
J. W. Mayer
Keyword(s):  
Grain Size ◽  
Grain Growth ◽  
Amorphous Layer ◽  
Crystal Nucleation ◽  
Initial Size ◽  
Diffusion Behavior ◽  
Transmission Electron ◽  
Average Grain Size ◽  
Si Films

ABSTRACTThe diffusion behavior of arsenic and the grain growth of Si in arsenic doped poly-Si were investigated by MeV4 He2+ backscattering techniques and transmission electron microscopy. By implanting arsenic ions into poly-Si films the surface portion was made amorphous and crystallized upon annealing. In-situ mssurements showed crystal nucleation and growth at temperatures of 650 – 700° C with a dimension comparable to the thickness of the amorphous layer. Annealing at temperatures up to 850°C increased the number of the large grains, but the average grain size did not change significantly. In the unimplanted region grains retained their initial size until 885°C, although implanted arsenic was found to diffuse into this region along grain boundaries. At 885°C penetration of arsenic into the interior of grains caused significant grain growth. We also found that single implants of boron somewhat increased grain size, whereas boron codoped with arsenic appeared to reduce the effect of arsenic doping. These observations support the hypothesis that the enhanced growth rate and the electrical activity of Si near the grain boundary are closely interrelated.

Production and Mechanical Properties of Nanocrystalline Intermetallics Based on TiAl3-X

2003 ◽  
Vol 791 ◽  
Author(s):  
H. A. Calderon ◽  
J. C. Aguilar-Virgen ◽  
F. Cruz-Gandarilla ◽  
M. Umemoto
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Grain Growth ◽  
High Strength ◽  
Compression Tests ◽  
Grain Sizes ◽  
Intermetallic Materials ◽  
Plasma Sintering ◽  
Average Grain Size ◽  
Spark Plasma

ABSTRACTProduction of intermetallic materials in the system TiAl3-X (X = Cr, Mn, Fe) has been achieved by means of mechanical milling and sintering techniques. Spark plasma sintering is used since it reduces time at high temperature and inhibits grain growth. The produced materials have grain sizes in the nano and microscale depending on the material and processing variables. The TiAl3-X alloys are formed mostly by the cubic L12 phase. The average grain size ranges between 30 and 50 nm in the as sintered condition. Aging at elevated temperature has been used to promote grain growth. Compression tests have been performed to evaluate mechanical properties as a function of temperature and grain size. In all cases yield stresses higher that 700 MPa are obtained together with a ductility that depends upon temperature and grain size. No ductility is found for the smallest grains sizes tested (30 nm) at room temperature. Above 673 K, these materials show ductility and additionally they present a quasi superplastic behavior at temperatures higher that 973 K. On the other hand ductility can also be developed in the TiAl3-X alloys by inducing grain growth via annealing. Alloys with grains sizes around 500 nm show high ductility and a large density of microcraks after deformation suggesting that the yield strenght becomes lower than the stress to propagate the cracks. In such materials, a considerably high strength is retained up to 873 K.

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