Texture in films and Coatings

1997 ◽  
Vol 472 ◽  
Author(s):  
J.A. Szpunar
Keyword(s):  
Grain Orientation ◽  
Grain Shape ◽  
Structural Parameters ◽  
Relative Proportion ◽  
Stacking Faults ◽  
Orientation Distribution ◽  
Film Structure ◽  
Frame Of Reference ◽  
Micro Structure ◽  
Physical Chemical

The field of films and coatings is very broad. In general, the structure of films may comprise several phases, each having a different micro-structure and composition. These phases may be built up from grains which have different sizes, shape, morphology and orientation. A description of those types of films is complex and a large number of structural parameters is needed to fully characterize them. It is therefore more convenient to use a statistical description of them and to specify the relative proportion of different phases, grain orientation distribution [1], the orientation correlation between neighbouring crystals [2] and grain shape and size distribution [3]. Such a description provides details of the microstructural geometry of films, thereby giving a frame of reference within which various properties of films and a microstructural transformation of film structure, can be analyzed. Such microstructural descriptions have to be often supplemented by information about the nature and distribution of lattice defects, dislocations, stacking faults and antiphase boundaries. All this information put together, helps to provide a better understanding of the behaviour and various physical, chemical, mechanical and other properties, of films and coatings.

Theoretical study of micro-structure fabrication by multi-beam laser interference lithography with different polarization combinations

2021 ◽  
pp. 2150459
Author(s):  
Xiangxian Wang ◽  
Tianxu Jia ◽  
Jiankai Zhu ◽  
Yingwen Su ◽  
Liping Zhang ◽  
...  
Keyword(s):  
Manufacturing Industry ◽  
Structural Parameters ◽  
Interference Lithography ◽  
Polarization Angle ◽  
Laser Interference Lithography ◽  
Laser Interference ◽  
Micro Structure ◽  
Periodic Patterns ◽  
Beam Laser ◽  
Micro Structures

In this study, we systematically and comprehensively investigated the influence of polarization angle on the fabrication of micro-structures by multi-beam laser interference lithography. Using theoretical analysis and simulation, we studied the effect of different polarization combinations, i.e. transverse electric (TE) and transverse magnetic (TM) polarization combinations, on the characteristics of the micro-structures fabricated by three-, four-, and six-beam laser interference lithography. We successfully obtained micro-structures with different periodic patterns such as honeycomb dots, quasi-elliptic dots, different square dots, and quasi-triangular dots. The simulation results illustrate that polarization affects the formation of interference patterns, pattern contrasts, and periods. The methods discussed herein are simple, low cost, and allow excellent control over structural parameters, and hence are useful for the micro-structure manufacturing industry.

Physical-Chemical Evolution of Hf-aluminates upon Thermal Treatments

2003 ◽  
Vol 765 ◽  
Author(s):  
B. Crivelli ◽  
M. Alessandri ◽  
S. Alberici ◽  
D. Brazzelli ◽  
A. C. Elbaz ◽  
...  
Keyword(s):  
Orthorhombic Phase ◽  
Interface Layer ◽  
Film Structure ◽  
Thermal Treatments ◽  
Tem Analysis ◽  
K Value ◽  
Physical Chemical ◽  
High K ◽  
Post Deposition ◽  
Limited Oxygen

AbstractThis study presents an investigation on physical-chemical stability of (HfO2)x(Al2O3 )1-x alloys upon prolonged post-deposition annealings. Two different Hf-aluminates were deposited by ALCVDTM, containing 34% and 74% Al2O3 mol% respectively. Post-deposition annealings (PDA) were carried out in O2 or N2 atmosphere, at 850°C and 900°C for 30 minutes. Interfacial layer (IL) increase after PDA was detected on all the samples, but with small differences between N2 and O2 treatments. Stack composition was characterized by means of XRR, XRF, RBS and TOF-SIMS. Growth of interface layer was justified by limited oxygen incorporation from external ambient. Silicon diffusion from the substrate into high-k material and aluminum/hafnium redistribution were observed and associated to annealing temperature. XRD and planar TEM analysis evidenced first grain formation and then, in the case of Hf-rich samples, almost complete crystallization. Overall, Hf-aluminates were found to remain XRD amorphous during high temperature prolonged treatments up to 900°C for 74% and 850°C for 34% alloys respectively. Differently from HfO2, (HfO2)0.66(Al2O3 )0.34 alloy was observed to crystallized in orthorhombic phase. Hf-aluminates were also electrically characterized by means of C(V) and I(V) measurements on basic capacitors. Variations in material electrical properties were found consistent with change in physical-chemical film structure. Increase in k value up to 30 was observed on Hf-rich samples crystallized in orthorhombic phase.

Effect of Grain Orientation Distribution on Anisotropy of Idealized Granular Materials

2012 ◽  
Vol 174-177 ◽  
pp. 24-29
Author(s):  
Bo Zhou ◽  
Ji Wei Li ◽  
Peng Shuai
Keyword(s):  
Granular Materials ◽  
Grain Orientation ◽  
Volumetric Strain ◽  
Friction Angle ◽  
Orientation Distribution ◽  
Biaxial Compression ◽  
Shape Effect ◽  
Vertical Loading ◽  
Horizontal Loading ◽  
Long Rod

Abstract. The regular grain orientation of granular materials is a common phenomenon in nature. Based on the research of grain shape effect on mechanical property of granular materials, two kinds of idealized shape grain (kind of long rod and square) assemblies with different grain orientation were studied by simulated biaxial compression test using Discrete Element Method. The significant orientation which can be computed as the mean value of all grain orientation is introduced to represent the orientation regularity of granular materials. In order to study the anisotropy, the mobilized friction angle and volumetric strain of assemblies with different significant orientation were obtained under both vertical and horizontal loading. The results show that the regular orientation of grains influences the movement such as motion and rotation obviously; with the increasing of significant orientation, peak mobilized friction angle of long rod grain assembly gradually increases under horizontal loading, and decreasing under vertical loading.

Mechanism of size effects in microcylindrical compression of pure copper considering grain orientation distribution

Rare Metals ◽  
2013 ◽  
Vol 32 (1) ◽  
pp. 18-24 ◽  
Author(s):  
Chuan-Jie Wang ◽  
Chun-Ju Wang ◽  
Bin Guo ◽  
De-Bin Shan ◽  
Yan-Yan Chang
Keyword(s):  
Size Effects ◽  
Grain Orientation ◽  
Pure Copper ◽  
Orientation Distribution

Role of grain orientation distribution in the ferroelectric and ferroelastic domain switching of ferroelectric polycrystals

2013 ◽  
Vol 61 (16) ◽  
pp. 6037-6049 ◽  
Author(s):  
J. Wang ◽  
W. Shu ◽  
T. Shimada ◽  
T. Kitamura ◽  
T.-Y. Zhang
Keyword(s):  
Grain Orientation ◽  
Domain Switching ◽  
Orientation Distribution

Atomic simulation of mechanical properties of irradiated iron

2019 ◽  
Vol 31 (02) ◽  
pp. 2050027
Author(s):  
Lei Ma ◽  
Changsheng Li ◽  
Ailong Zhang ◽  
Wangyu Hu
Keyword(s):  
Crystal Structure ◽  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Tensile Test ◽  
Room Temperature ◽  
Stacking Faults ◽  
Dynamics Simulation ◽  
Stress And Strain ◽  
Micro Structure ◽  
Atomic Simulation

The mechanical properties of irradiated iron are studied by molecular dynamics simulation. The initial models are irradiated with the energy of primary knocked-on atoms (PKA) of 10[Formula: see text]keV at 100, 300, 500 and 600 K, and then all the irradiated models are subjected to tensile test. The results reveal that the mechanical properties of irradiated iron are changed compared with un-irradiated iron, the yield stress and strain decrease after irradiation, and the irradiation causes the hardening of micro-structure at low temperature and high temperature, but it results in the softening of structure at room temperature. The plastic reduces for irradiated iron under tensile test, more stacking faults are formed in the crystal structure as the temperature increases.

Cast NiTi Shape-Memory Alloys

2004 ◽  
Vol 855 ◽  
Author(s):  
Alicia M. Ortega ◽  
Carl P. Frick ◽  
Jeffrey Tyber ◽  
Ken Gall ◽  
Hans J. Maier
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Grain Orientation ◽  
Mechanical Response ◽  
Complex Geometry ◽  
Low Cost ◽  
Orientation Distribution ◽  
Scanning Calorimetry ◽  
Cast Material ◽  
Niti Shape Memory Alloys

ABSTRACTThe purpose of this study is to investigate the structure and properties of polycrystalline NiTi in its cast form. Although it is commonly stated in the literature that cast NiTi has poor shape-memory behavior, this study demonstrates that with appropriate nano/micro structural design, cast NiTi possesses excellent shape-memory properties. Cast NiTi shape-memory alloys may give rise to a new palette of low-cost, complex-geometry components. Results from two different nominal compositions of cast NiTi are presented: 50.1 at.%Ni and 50.9 at.%Ni. The cast NiTi showed a spatial variance in grain size and a random grain orientation distribution throughout the cast material. However, small variances in the thermo-mechanical response of the cast material resulted. Transformation temperatures were slightly influenced by the radial location from which the material was extracted from the casting, showing a change in Differential Scanning Calorimetry peak diffuseness as well as a change in transformation sequence for the 50.9 at.%Ni material. Mildly aged 50.9 at.%Ni material was capable of full shape-memory strain recovery after being strained to 5% under compression, while the 50.1 at.%Ni demonstrated residual plastic strains of around 1.5%. The isotropic and symmetric response under tensile and compressive loading is a result of the measured random grain orientation distribution. The favorable recovery properties in the cast material are primarily attributed to the presence of nanometer scale precipitates, which inhibit dislocation motion and favor the martensitic transformation.

The Origin of Mis-Oriented Diamond Grains Nucleated Directly on (001) Silicon Surface

1998 ◽  
Vol 529 ◽  
Author(s):  
R.Q. Zhang ◽  
W.J. Zhang ◽  
C. Sun ◽  
X. Jiang ◽  
S.-T. Lee
Keyword(s):  
Grain Orientation ◽  
Silicon Surface ◽  
Diamond Films ◽  
Orientation Distribution ◽  
Interface Structure ◽  
Silicon Surfaces ◽  
Diamond Growth ◽  
Diamond Nucleation ◽  
Interfacial Structures ◽  
Zero Degree

AbstractThe origin of mis-oriented diamond grains frequently observed in heteroepitaxial diamond films on (001) silicon surfaces was studied. By statistically analyzing the in-plane rotation angles of diamond grains in scanning electron microscopy observations, it was found that the distribution of the grain orientation is not random and two satellite distribution peaks at about 20° and 30° accompany the main distribution peak at zero degree referenced to the <110> direction of substrate. The interface structure corresponding to the main distribution peak at zero degree of oriented diamond growth has been proposed in our previous studies. In this study, our molecular orbital PM3 simulation of a step-by-step diamond nucleation further reveals two other metastable diamond/silicon interfacial structures. The orientations of the corresponding diamond grains are parallel to the (001) silicon surface but with in-plane rotations of 20° and 30° respectively with respect to the <110> direction. We relate these two mis-oriented growths to the two satellite peaks of grain orientation distribution. Based on this study, the possibility in experiment to reduce the formation of mis-oriented configurations and to obtain a perfectly oriented diamond growth is discussed.

scholarly journals Bayesian inference of metal oxide ultrathin film structure based on crystal truncation rod measurements

2017 ◽  
Vol 50 (6) ◽  
pp. 1611-1616 ◽  
Author(s):  
Masato Anada ◽  
Yoshinori Nakanishi-Ohno ◽  
Masato Okada ◽  
Tsuyoshi Kimura ◽  
Yusuke Wakabayashi
Keyword(s):  
Bayesian Inference ◽  
Structural Parameters ◽  
Film Structure ◽  
Perovskite Oxide ◽  
Local Optima ◽  
Domain Structures ◽  
Crystal Truncation Rod ◽  
Global Optima ◽  
Optimum Model ◽  
Simulated Annealing Procedure

Monte Carlo (MC)-based refinement software to analyze the atomic arrangements of perovskite oxide ultrathin films from the crystal truncation rod intensity is developed on the basis of Bayesian inference. The advantages of the MC approach are (i) it is applicable to multi-domain structures, (ii) it provides the posterior probability of structures through Bayes' theorem, which allows one to evaluate the uncertainty of estimated structural parameters, and (iii) one can involve any information provided by other experiments and theories. The simulated annealing procedure efficiently searches for the optimum model owing to its stochastic updates, regardless of the initial values, without being trapped by local optima. The performance of the software is examined with a five-unit-cell-thick LaAlO3film fabricated on top of SrTiO3. The software successfully found the global optima from an initial model prepared by a small grid search calculation. The standard deviations of the atomic positions derived from a dataset taken at a second-generation synchrotron are ±0.02 Å for metal sites and ±0.03 Å for oxygen sites.

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