bluuebunny/crossref_metadata_2025 huggingface dataset:
Applying a Uniform Design of Experiment Approach for Reducing Injection Moulding Warpage Deflection
Authors: Deng Yi Min , Wang Li Zhu
Published: June 2010

Injection moulding is an efficient means for producing plastic products in large quantities. Warpage deflection is one of the most severe defects occurring to the moulded plastic parts. In this paper, we report a novel method for reducing warpage deflection by applying a Uniform Design of Experiment (UDE) method. UDE is an experimental approach that is able to distribute experiments evenly within experimental space, especially when large number of experimental levels is necessary. We describe the method with a case study, for which the experimental table is developed and the procedure for the application of the method is elaborated. The results demonstrate that the method is effective for reducing injection moulding warpage deflection, and it is relatively more efficient than other means of DOE (Design of Experiment) approaches
Critical Undeformed Chip Thickness and Cutting Pressure in Relation to Ductile Mode Cutting of KDP Crystal
Authors: Chen Hao Feng , Zheng Zi Wen , Dai Yi Fan , Gao Hang , Li Xiao Ping
Published: June 2010

Microgroove processes are carried out on Potassium Dihydrogen Phosphate (KDP) crystals of different crystalline orientation using diamond tool, the speed of groove is very low in order to avoid the influence of temperature. The main process characteristics are examined including the groove geometry, cutting forces and critical underformed chip thickness at the onset of ductile-to-brittle cutting transition. Additionally, the cutting pressure is calculated from the cutting force and grooving geometry. The experimental results show that as the groove depth increase, the groove geometry clearly revealed that ductile-to-brittle cutting transition occurred, and the transition are well reflected by changing in the cutting pressure. Further, it is shown that the critical undeformed chip thickness varies greatly with the workpiece KDP crystalline orientation.
Influence of the Workpiece Crystallographic Orientation on Ultra-Precision Turning of KDP Crystals
Authors: Zheng Zi Wen , Gao Hang , Li Xiao Ping
Published: June 2010

The mechanical properties of Potassium Dihydrogen Phosphate (KDP) crystal had been relatively well investigated, and it was reported that mechanical properties of KDP crystal are anisotropic corresponding to crystallography orientation. However, the affect of the crystallography orientation to the critical undeformed chip thickness and cutting force variation in ductile mode cutting of KDP crystal are still not clear, which are important in determining proper cutting parameters to get fine finished surface. This paper investigates the influence of crystallographic orientation to critical undeformed chip thickness by a kind of groove cutting on {001} plane, and the influence to cutting force is also researched by face turning. The experiment results demonstrate that the cutting forces and critical undeformed chip thickness for ductile mode cutting varies greatly according to KDP crystallographic orientation. This paper point out that two slipping plane, {110} and {1__,10}, account for the variation of cutting force and critical undeformed chip thickness in different orientation on {001} plane. A set of cutting parameters for ductile mode cutting are selected based on the derived critical undeformed chip thicknesses at different crystal orientations, and overall sooth surface has been achieved on face turned {001} surface, which the roughness is Ra 2.6nm measured by Veeco white-light interferometer.
Evaluation of Novel Approach on Delamination Factor after Drilling Composite Laminates
Authors: Tsao Chung Chen , Kuo Kei Lin , Hsu I Chien
Published: June 2010

Drilling is the most economic and convenient operation of secondary machining for hole making of fiber-reinforced materials owing to the need for structure joining. Delamination is commonly recognized as a major defect after drilling composite materials. In general, the delamination is an irregular shape and size, containing long and fine breaks and cracks at the exit of the drilled hole, especially in the drilling of carbon fiber-reinforced plastic (CFRP). The conventional delamination factor ( ) is not appropriated to characterize the damage area because the shape of the delamination after drilled CFRP is not a regular representation of the damage magnitude. In this paper, a novel approach of the equivalent delamination factor ( ) is proposed and compared with the adjusted delamination factor ( ) and the conventional delamination factor ( ). The experimental results show the obtained is considered suitable for characterizing delamination at the exit of a hole after drilling composite materials.
Application of the Grey-Taguchi Method to the Optimization of Metal Injection Molding (MIM) Process
Authors: Jamaludin Khairur Rijal , Muhamad Norhamidi , Rahman Mohd Nizam Ab. , Ahmad Sufizar , Ibrahim Mohd Halim Irwan , Nor Nor Hafiez Mohamad , Daud M.Y.M.
Published: June 2010

The Grey-Taguchi method was adopted in this study to optimize the injection molding parameters for the MIM green compacts with multiple quality performance. A Grey relational grade obtained from the Grey relational analysis is used as the quality performance in the Taguchi method. Then, the optimum injection molding parameters are determined using the parameter design proposed by the Taguchi method. The result concluded that the mold temperature (D) is very significant, by the fact that the ANOVA shows its contribution to excellent surface appearance as well as strong and dense green compacts is 38.82%.
Process Technology and Performance Evaluation of Nylon 6/PU Stab Resistance Fabric Matrix
Authors: Lee Cho Hsun , Lou Ching Wen , Chen Jin Mao , Liang Hung Jui , Lin Jia Horng
Published: June 2010

Stab resistance compound fabric is frequently used in daily life, industry, military and aerospace. In this study, Nylon 6 and Polyester short fibers were mixed in ratio of 70:30. The mixture was needle punched at speed 300 needle/min to form a stab resistant fabric. The non-woven fabric matrix, non-woven fabric/grid matrix, non-woven/water-bone polyurethane (PU), and matrix/grid/water-bone PU, were put to test their tensile stress, tear stress, and stab resistance. Latter, the most stab resistant compound matrix was constructed in lamination structures to examine the relationship between thickness and stab resistance. The result showed that stab resistance of the non-woven/grid/water-bone PU compound fabric was 115 N; the triple-layered sample D was 208 N.
Modelling and Simulation of Cutting Forces in Micromachining
Authors: Rahman Shah Md. Mahfuzur , Liow Jong Leng
Published: June 2010

The analysis of cutting forces plays an important role in the design of machine tool systems as well as in the planning, optimization, and control of micro machining processes. Several parameters influence the cutting forces of which the friction is important in causing premature tool failure. This paper presents a force model that includes the friction force for sliding due to the contact between the tool and workpiece at the flank face. Simulation results were compared with the experimental results of Bao and Tansel [1] showing that the model can satisfactorily represent the cutting forces in two dimensional cutting.
Erosion Mechanism of Ultrasonic Vibration Abrasive Waterjet in Micro Machining
Authors: Zhu Hong Tao , Huang Chuan Zhen , Wang Jun , Liu Zeng Wen , Zhang Shu Guang
Published: June 2010

In this paper, a study on erosion mechanism of Ultrasonic Vibration Abrasive Waterjet is presented. Theoretical analysis of the total effective erosion kinetic energy of UVAWJ is performed. By using a UVAWJ machining system with an Ultrasonic Vibration Power Workbench, the comparative experiment is conducted. The erosion surfaces of the single crystal silicon substrate were measured by Optical Profiler and observed with Scanning Electron Microscope. The material removal mechanisms are discussed. It is concluded that the erosion by UVAWJ, with the aid of high-frequency ultrasonic vibration, can obtains a high material removal, less cracks and good finish surface.
Surface Modification of Plastic Thin Film Using Anodic Aluminum Oxide Template for Nano Imprint
Authors: Wu Chih Wei , Lee Jeou Long , Lin Yi , Shen Yung Kang
Published: June 2010

Nano-porous anodic alumina oxide (AAO) templates are fabricated by anodizing method. The average diameter of nano-porous anodic alumina is 200 nm. The molded plastic thin film (Polycarbonate, PC) with nano-structure is fabricated by AAO as mold insert for nanoimprint. This research discusses the surface property of molded plastic thin film for different processing parameters (embossing temperature, embossing pressure, embossing time, de-molding temperature) on nanoimprint. The original contact angle of PC material without nano-structrue is about 78.2°. The contact angle of molded PC with nano-structrue is about 115.5°. The contact angle of molded plastic film (PC) with nano-structure is larger than that without nano-structure. The hydrophilic property of PC material has changed to hydrophobic property. A significant advantage of the fabrication process employed in this work is that it can create the good surface modification of plastic thin film.
Possible Chemical Bond Formation between a Carbon Nanotube and Alumina Matrix - A Quantum Mechanics Investigation
Authors: Mylvaganam Kausala , Zhang Liang Chi
Published: June 2010

To improve the structural properties of engineering ceramics, carbon nanotubes have been used as a reinforcement phase to produce stronger ceramic matrix composites. This paper investigates the possible chemical bond formation between a carbon nanotube and alumina with the aid of quantum mechanics analysis. The cases with and without functionalizing the nanotubes were examined. The nanotubes were modeled by nanotube segments with hydrogen atoms added to the dangling bonds of the perimeter carbons. The cleaved ceramic (0001) surface was represented by an alumina molecule with the oxygen atoms on either end terminated with hydrogen. Methoxy radicals were used to functionalize the CNTs. The study predicts that covalent bonding between Al atoms on a cleaved single crystal alumina surface and C atoms on a nanotube are energetically favorable.
Minimizing Stress Concentrations in the Femoral Heads of Hip Joint Prostheses: Effect of Borehole Shapes
Authors: Uddin Mohammad Sharif , Zhang Liang Chi
Published: June 2010

This paper presents a stress analysis of the ceramic femoral heads of hip joint prostheses with different borehole shapes to evaluate their mechanical reliability in terms of stress concentration. Under the ideal loading conditions used for ceramic rupture tests specified by the ISO 7206-5 standard, a finite element (FE) modeling is performed to determine the tensile and hoop stress distributions in the ceramic femoral heads. Two borehole shapes that are currently used in the manufacturing industry for hip joint prostheses, namely the flat bottom and keyhole, were first studied. Two new borehole shapes, dome arc and dome ellipse, were then introduced by the authors in the paper to minimize the stress concentration. It was found that while the currently used borehole shapes lead to high tensile notch stresses at their critical corners causing possible fracture failure of ceramic heads, the authors’ borehole designs can improve the mechanical reliability significantly. In addition, the effects of taper-bore contact length and their interface friction are investigated and discussed.
Determining the Complete Residual Stress Tensors in SOS Hetero-Epitaxial Thin Film Systems by the Technique of X-Ray Diffraction
Authors: Liu Mei , Zhang Liang Chi , Brawley Andrew , Atanackovic Petar , Duvall Steven
Published: June 2010

This paper investigates residual stress of epitaxial silicon film on SOS thin film systems. The emphasis was to develop a method to obtain accurately the complete residual stress tensors. It was found that using the multiple asymmetric X-ray diffraction method to measure strains in 13 [hkl] directions, the complete residual stress tensors can be determined reliably. The results were verified by both the Raman Backscattering and the substrate curvature methods.
The Construction of Production Improvement Model for Aerospace Manufacturing Suppliers
Authors: Chang Hsien Ming , Huang Chi Kong , Torng Chau Chen
Published: June 2010

Aerospace industry is a value-added and technology integrated industry. Due to the investment of aerospace industry is high and the pay back period is long, the type of aircraft production belongs to make-to-order system. Business flows and process flows are complex inside the aerospace manufacturing industry. Quality, cost, delivery and flexibility are the fundamental requirements of aerospace manufacturing suppliers. The aerospace manufacturing suppliers have to coordinate those fundamental requirements and construct the model of production system with Continuous Improvement in the competitive market. This study integrates the concepts of Six Sigma, Theory of Constraint, Lean Production and Value Engineering, and allies the functional groups and system resources inside the aerospace manufacturing suppliers. Then develop the Production Improvement Model with Continuous Improvement to allocate the resources to construct a production system. Thereby, the aerospace manufacturing suppliers can strengthen the competitiveness in the dynamic aerospace market.
Study of Metal Powder Extrusion and Accumulating Rapid Prototyping
Authors: Li Ji Bin , Xie Zhan Gong , Zhang Xiao Hui , Zeng Qi Gao , Liu Hai Jun
Published: June 2010

A new method, namely Metal Powder Extrusion & Stacking Modeling is proposed in this paper based on RP and Metal Injection Molding (MIM) principle. Stainless steel powder and thermoplastic paraffin wax-based binder are used in our experiment. Firstly, feedstock is generated by mixing power and binder in a rotor internal mixer. Then the granular feedstock is put into screw-extruder devices to extruded filament, and accumulating green part at atmospheric status. Finally, green part is thermal defatted and sintered in hydrogen atmosphere to product the sintered parts. The testing results are as follows. The density of our RP product is 73.75%. The average shrinkage rate is 7.51%, 18.00%, and 29.31%, for diameter, thickness and volume respectively. Brinell hardness is HB77.52, while bending strength is 457MPa and tensile strength is 163Mpa. The experimental results verify that our proposed method is promising.
Advanced Input Files & Parametric Quantitative Analysis Using Topas
Authors: Evans John S.O.
Published: June 2010

Topas is a powerful and flexible software suite for the analysis of powder diffraction (and other) data. In this paper we describe methods to interact with the software in efficient and customisable ways. We also provide brief details of a wiki site for sharing ideas and methods for this software (topas.dur.ac.uk). Finally we give an overview of the potential advantages of parametric refinement methods within Topas and exemplify them with a quantitative analysis study of the phase transitions in WO3.
MEM Calculations on Apatites Containing Peroxide Using BAYMEM and TOPAS
Authors: Samy Ali , Dinnebier Robert E. , Kazin Pavel E. , van Smaalen Sander , Jansen Martin
Published: June 2010

A set of macros for the powerful least squares and global optimization program TOPAS has been written in order to create a user friendly interface to the maximum entropy method (MEM) program BayMem. As a case study, the crystal structures of pure strontium hydroxyl apatite and strontium hydroxyl apatite with approximately 10% of the hydroxyl anions substituted by peroxide anions were analyzed by TOPAS and BayMem. Although the concentration of peroxide is relatively small, distinct differences in the two crystal structures could be made visible by the MEM.
Protein Powder Diffraction Analysis with TOPAS
Authors: Watier Yves , Fitch Andy
Published: June 2010

While various software packages exist to study powder patterns, few are accessible
to beginners and yet remain highly customisable. In this paper we will give guidelines for
biologists interested in analysing powder patterns of proteins with Topas. Several topics will
be discussed, from basic methods like indexing on a restricted list of spacegroups, to advanced
use of command input les for pattern modelling and rigid body renement.
Composition-Induced Microstrain Broadening: From Pattern Decomposition to whole Powder Pattern Modelling Procedures
Authors: Leineweber Andreas
Published: June 2010

Microstrain broadening due to composition variations in -FeN0.407 has been evaluated using different evaluation procedures ranging from pattern decomposition to whole-powder-pattern modelling. Details how to set up these procedures in the TOPAS suite of programs have been described. The different procedures yield essentially the same results, but they have their advantages and disadvantages, which are discussed.
WPPM: Advances in the Modeling of Dislocation Line Broadening
Authors: Leoni Matteo , Martinez-Garcia Jorge , Scardi Paolo
Published: June 2010

Whole Powder Pattern Modeling (WPPM) is especially useful to study line defects in powder and polycrystalline materials. As a result of recent progresses in this field, dislocation studies can be carried out for any slip system and crystal symmetry of the studied phases. Basic theory and procedures are described with the help of some representative cases of study. The use of the dislocation-related broadening in the PM2K software implementing the WPPM approach is shown with practical examples.
The Application of the Fundamental Parameters Approach as Implemented in TOPAS to Divergent Beam Powder Diffraction Data
Authors: Cline James P. , Black David R. , Gil David , Henins Albert , Windover Donald
Published: June 2010

The fundamental parameters approach (FPA) as implemented in TOPAS is investigated for analyses of conventional X-ray powder diffraction (XRPD) data. The FPA involves the convolution of a series of models, each one constituting an individual contribution to the geometric portion of the instrument profile function (IPF). Parameters within each model are refined by least squares to yield a presumably accurate description of the experiment. If one wishes to interrogate the functionality of said models, a diffractometer wherein the uncertainties in optical character are minimized is required. To this end, a diffractometer was built at NIST which featured conventional divergent beam optics in conjunction with a well aligned, stiff, and accurate goniometer assembly. Initial results indicated that the detector arm was flexing; this problem has been addressed with the fabrication and installation of a new arm and counterweight assembly. Data collected from NIST Standard Reference Material (SRM) 660a, lanthanum hexaboride, are analyzed using the FPA method to yield conclusions on the validity of the models with respect to shape and position of the diffraction profiles.
Robust Refinement as Implemented in TOPAS
Authors: Stone Kevin H. , Stephens P.W.
Published: June 2010

A robust refinement procedure is implemented in the program TOPAS through an iterative reweighting of the data. Examples are given of the procedure as applied to fitting partially overlapped peaks by full and partial models and also of the structures of ibuprofen and acetaminophen in the presence of unmodeled impurity contributions.
Simulated Annealing Approach for Global Minimum Verification in Modeling of Pressure-Volume Dependence by Equations of State Obtained by High-Pressure Diffraction
Authors: Halasz Ivan , Dinnebier Robert E.
Published: June 2010

A simulated annealing like optimization method has been successfully applied for the determination of global minimum of equation of state (EoS) parameters. The approach is tested using the program TOPAS on a high precision variable pressure data set of quartz [R.J. Angel, D.R. Allan, R. Miletich, L.W. Finger: J. Appl. Cryst. Vol 30 (1997) p. 461] It is evidenced that least-squares refinement finds the global minimum for all EoS except for the Birch-Murnaghan EoS of fourth order for which it is shown that a clearly distinguished global minimum does not exist, at least for the used data set. The method presented herein serves as a fast test for the global minimum verification for the EoS parameters but should be applicable also to other optimisation problems.
Optimization of Material Properties Using Genetic Algorithms
Authors: Wierzbanowski Krzysztof , Tarasiuk Jacek , Lodini Alain
Published: June 2010

The genetic algorithm method was used in the present work as an alternative to classical calculation methods. It can be used in the situations where we search an optimal solution and a problem has many variable parameters. In this work the genetic algorithm method was applied in order to decompose the texture function into ideal components and also to optimize elastic constants by an appropriate choice of texture function. These example applications of genetic algorithm method show its potential in the field of material engineering.
Residual Stresses in Overlapping Friction Taper Stud Welds
Authors: Hattingh D.G. , Steuwer Axel , James M. Neil , Wedderburn I.N.
Published: June 2010

This paper presents microstructural, hardness and residual strain information for solid-state welds in creep-resistant Cr-Mo steel, made using the new local damage repair technique offered by friction taper stud welding (FTSW). The technique is suitable for making single welds to repair, for example, localised creep damage but can also be extended to deal with planar defects through the use of overlapping welds. Neutron diffraction was used to measure residual strains at a number of positions along a series of 5 overlapping FTS welds.
Investigation of Residual Stress in Laser Formed Mild Steel Plates Using Neutron Diffraction
Authors: Knupfer Stefan M. , Paradowska Anna Maria , Kirstein Oliver , Moore Andrew
Published: June 2010

Forming of metal plates with a high-power laser beam is a flexible materials forming technique. Bending results from the establishment of a steep temperature gradient through the material thickness which leads to non-uniform thermal expansion/contraction and subsequently residual stresses. It is important to characterize these residual stresses as a function of process parameters such as line energy (LE) to optimize treatment conditions and to gain an insight into the mechanism of the formation of the final geometries. Non-destructive neutron diffraction measurements were carried out on ENGIN-X at ISIS and KOWARI at ANSTO to map the residual stress distribution around the heat affected zone (HAZ) of laser deformed mild steel plates for single and multiple passes as a function of line energy (LE), the primary laser forming process parameter. It was found that in the centre of the HAZ, longitudinal residual stresses are tensile and dominant, transverse stresses are predominantly tensile and normal stresses are compressive and close to zero. The residual strain in longitudinal direction increased with LE and number of passes until yielding. Even higher heat input decreased the magnitude of the cusp, but not its total height. The comparison of a stress-free reference sample, measured at both facilities, showed a small discrepancy in the lattice spacing corresponding to ~ 85 μstrain which is insignificant with respect to the experimental values measured.
Search for Evidence of Stacking Faults in Austenitic Stainless Steel Alloys by Neutron Diffraction
Authors: Holden Thomas , Brown Donald W. , Clausen Bjørn , Suzuki Hiroshi
Published: June 2010

Neutron diffraction measurements of strain in austenitic stainless steel alloys are presented to examine whether there are contributions to the shifts from deformation induced stacking faults. Differences between successive orders of reflections are consistent with the presence of stacking faults for 316 stainless steel but not for a NiCrFe steel.
Intergranular Strains in Pre-Strained and Welded Pipes
Authors: Acar M.O. , Bouchard P. John , da Fonseca Joao Quinta , Fitzpatrick Michael E. , Gungor S.
Published: June 2010

Neutron diffraction has been used to investigate the weld residual stresses and the intergranular residual strains in butt-welded 316H pipes. Measurements have been made on pipes subjected to varying degrees of plastic pre-straining before welding, in order to assess the effects of plastic strain on the weld residual stresses and the intergranular strains in the material. The intergranular strains following plastic deformation will also be affected by the annealing effect of the welding. Pipes were initially prepared with plastic strain of 0, 10, 15, 20 and 25% plastic deformation. Thereafter, the pipes were cut in half and welded with a circumferential butt-weld. Bar specimens were extracted from the remote end of the 0, 10, 15, 20 and 25% pre-strained and welded pipes. Cross-weld bar specimens were also machined from the 0 and 20% pre-strained and welded pipes. Neutron diffraction measurements were made at ENGIN-X, ISIS and FRM-II, Munich. The aim of this paper is to evaluate the intergranular strains developed after pre-straining from measurements made in remote bar specimens from the remote-end of the pipes. The annealing effect of the welding cycle on the intergranular strains is also studied, with measurements done at several points on cross-weld bar specimens, obtaining the strain response of different hkl lattice planes. The results show that the {200} and {220} planes are at the extremes of response during loading. Furthermore, the welding thermal cycling relaxed the intergranular strains from the prior plastic deformation.
Residual Stress Evaluation at Bone Implant Interfaces Using High Energy X-Ray Diffraction
Authors: Mireux Bastien , Buslaps Thomas , Honkimäki Veijo , Lodini Alain , Sprauel Jean Michel
Published: June 2010

The present study is dedicated to high energy x-ray diffraction measurements of residual stress at bone-implant interfaces. Bone regeneration is different from soft tissue repair as scar formation never occurs and as de novo bone tissue is produced with proliferation and differentiation of mesenchymal cells. To start the bone remodelling, the stress – the most important mechanical factor – should stimulate the osteocytes. Osseointegration is also observed with non-functional implants, in particular with dental implants. This means that a stress similar to a residual stress must exist.
Characterization of New Bone Constituted at the Interface with Implant by Synchrotron Radiation
Authors: Benmarouane Abdelilah , Citterio-Bigot Helene , Millet Pierre , Buslaps Thomas , Lodini Alain
Published: June 2010

Technology developments of implant composition and manufacture have been used in the medical field. Several different implants have been developed with varying degrees of commercial success. As a long-term establishment is a measure of the therapeutic success, it is necessary to use biocompatible implants in order to have good mechanical and fracture resistance of new bone reconstructed at the interface with the implant.
Titanium (Ti-Al-4V) implants coated with hydroxyapatite (HAp), Ca10 (PO4)6 (OH)2 are widely used in orthopedic applications in order to obtain a stable and functional direct connection between the bone and the implant. At the implant-bone interface the new bone reconstituted after implantation must have the same orientation as the natural bone in order to accept the implant. Therefore we studied the texture and the crystallinity of the new bone crystals reconstituted at the interface applying by high-energy synchrotron radiation on beamline ID15 at ESRF in Grenoble, France.
Synchrotron Strain Mapping of the Residual Strain Distribution around Foreign Object Damage in Laser Shock Peened Ti-6AL-4V Alloy
Authors: Zabeen Suraiya , Preuss Michael , Withers Philip J. , Spanrad Sven , Tong Jie , Schofield John
Published: June 2010

The current study investigates the effect of foreign object damage (FOD) on the pre-existing compressive residual stress field associated with laser shock peening (LSP) and its evolution upon combined LCF/HCF cycling. FOD was introduced onto an aerofoil-shaped specimen that had been previously LSP treated through ballistic impacts at angles of 0° and 45° to the leading edge. It is shown that the FOD notch created by 45° impact was asymmetric in shape and smaller in depth compared to that created at 0° impact. Significant through thickness compression was introduced parallel to the leading edge as a result of the LSP process. The residual strain distribution was mapped around the FOD notch by synchrotron X-ray radiation. The results show predominantly compressive stresses ahead of the notch, being greater for the 0 compared to 45 impact. No significant stress relaxation was observed after a combined (1000 HCF cycles superimposed on 1 LCF cycle) cycle.
Thermal and Mechanical Response of Industrial Porous Ceramics
Authors: Bruno Giovanni , Efremov Alexander M. , Levandovskiy Andrey N. , Pozdnyakova Irina , Hughes Darren J. , Clausen Bjørn
Published: June 2010

In this study, the mechanical behavior of porous thermally microcracked ceramics has been compared with that of solely porous materials, under compressive applied stress. The different aspects of the micro and macroscopic stress-strain curves have been inserted into a coherent analytical model and compared with finite element modeling calculations. The agreement between experiments and models is very good.
It is shown that mechanical microcracking, as opposed to thermal, introduces an irreversible aspect in the deformation mechanisms of porous ceramics. In this concern, mechanical loads differentiate themselves from thermal cycling. This leads for instance to a change of the Young’s modulus as a function of applied load, which qualifies those materials as visco-elastic.
Hybrid Measurement of CT and Strain Distribution of Internal Crack Using Synchrotron High-Energy Monochromatic X-Rays
Authors: Tanaka Keisuke , Shobu Takahisa , Kimachi Hiroshi
Published: June 2010

Using high-energy monochromatic X-rays of energy 66.4keV from the synchrotron radiation source, SPring-8, we have developed a system to perform a hybrid measurement of imaging of cracks and strain distribution around cracks. This system was applied to a fatigue crack made in a round bar made of carbon steel with a diameter of 4 mm. Computed tomography of the specimen gave the three-dimensional shape of a thumb-nail crack. High tensile strain ahead of the crack was measured at the applied maximum stress, while the strain on the crack face was low because of stress relief due to crack opening. The full width at half maximum (FWHM) increased near the crack tip under loading, and then decreased after unloading. The recoverable part of FWHM by unloading was caused by the steep distribution of the applied stress in the vicinity of the crack tip. The FWHM increased by plastic deformation does not change when unloaded. The measured distributions of the lattice strain and FWHM agreed well with those of the elastic and plastic strains calculated by the finite element method, respectively.
Effect of Initial Residual Stress on Stress Relaxation in Cold-Drawn Steel Rods
Authors: Ruiz-Hervias Jesus , Atienza Jose M. , Santisteban Javier R. , Elices Calafat Manuel
Published: June 2010

This work shows the effect of the initial residual stress state on the stress relaxation behavior of cold-drawn steel rods. The evolution of residual strains at several locations along the rod diameter was measured in-situ by neutron diffraction during a stress relaxation experiment. It was found that if residual stresses are significant, stress relaxation is not homogeneous in the cross-section of the rods. This also explains the higher stress losses found in the rods with high residual stresses.
Application Software Development for the Engineering Materials Diffractometer, TAKUMI
Authors: Ito Takayoshi , Nakatani Takeshi , Harjo Stefanus , Arima Hiroshi , Abe Jun , Aizawa Kazuya , Moriai Atsushi
Published: June 2010

The Engineering Materials Diffractometer Application Kit called EMAKi has been developed to control the Engineering Materials Diffractometer, TAKUMI, and treat data obtained by it. It is expected that TAKUMI will be widely used by not only academic users but also industrial users. We have designed EMAKi to be user-friendly interface for novice users by graphical user interface (GUI). In addition, adopting Python programming language for its development has enabled advanced users to control the diffractometer flexibly and treat the data easily. During instrumentation commissioning and running user programs, the software has demonstrated useful.
Neutron Stress Measurement of Coarse Crystal Grain in Aluminum Casting Alloy
Authors: Masayuki Nishida , Takao Hanabusa , Matsue Tatsuya , Suzuki Hiroshi
Published: June 2010

Internal stresses in aluminum casting alloy were measured by the neutron stress measurement method with the apparatus RESA in Japan Atomic Energy Agency (JAEA). In usual cases, coarse crystal grains are included in aluminum casting alloy. These coarse crystal grains make it extremely difficult to estimate the internal stresses by the neutron diffraction [1]. The two problems arise because of the existence of the coarse crystal grains. The first problem is the production of an unstable diffraction profile in the necessary direction. The second is the edge effect which is generated by the overhang of the coarse crystal grains from the neutron irradiation area (gage volume). In this study, two kinds of new techniques used were proposed to resolve these problems. Firstly, the elastic theory based on the sin2ψ method is shown. Diffraction peaks in several directions were found by use of the rocking curve method. Following that, the lattice spaces in each principal direction were calculated from these diffraction peaks using the elastic theory. Secondly, the distribution of edge effect around the gage volume was measured using a small bit of copper single crystal. From this result, the edge effect was canceled out by the modified measurement method which was done symmetrically. Finally, the aluminum casting sample which included coarse crystal grains was set to the tensile testing machine on RESA’s measurement table and the applicability of these new techniques were confirmed experimentally.
Application of Göbel Mirror for Stress Measurement Using Grazing Incidence Geometry
Authors: Baczmanski Andrzej , Marciszko Marianna , Wierzbanowski Krzysztof , Buturyn Grzegorz , Bonarski Jan T. , Tarkowski Leszek
Published: June 2010

The Göbel mirror allows parallelization of the divergent X-ray beam leading to its higher intensity. Perfectly collimated (parallel) beam radically decreases errors of determined peak position in diffraction experiments. In the present work the Göbel mirror was applied for stress measurements using grazing incidence geometry.
Investigation on Microstructures of Multipass Deposited Metal for 9Cr-1Mo Ferritic Steels
Authors: Wang H.H. , Wu Kai Ming
Published: June 2010

The microstructures of multipass deposited metal for 9Cr-1Mo ferritic steels were investigated. Columnar martensites and a number of film austenites retained along the lath of martensite comprised primary microstructure. -ferrite was formed and the volume fraction of -ferrite increased as the chromium equivalent (Creq) of steel composition increased. Subjected to weld heating, the primary microstructure transformed. “Weld bead heat-affected zone (WBHAZ)” was thus formed. The morphology of -ferrite changed and columnar martensite grains were broken in sub-zone I and II of WBHAZ. The size and amount of -ferrite reduced because of austenitization and growth of austenite in sub-zone III of WBHAZ. Retained austenite morphology changed from film into island-like in sub-zone IV and martensite tempered to some degree in sub-zone V of WBHAZ. The precipitation and evolution of M23C6, MX and Laves phase by means of neutron diffraction is to be conducted in the future.
Weldability of a Low Carbon High Strength Ti-Containing Bainitic Steel Produced by CSP
Authors: Wei Ran , Cheng Lin , Wu Kai Ming
Published: June 2010

The weldability of a 700 MPa grade low carbon Ti-containing microalloyed bainitic steel produced by compact strip production (CSP) has been investigated by gas metal arc welding. Microstructural features of the welded joint of the investigated steel have been investigated utilizing optical and scanning electron microscopy (SEM). The microstructures in the heat affected zone (HAZ) consist of a predominantly bainitic ferrite and a proportion of acicular ferrite which formed on Ti-oxide and/or nitride particles. The acicular ferrite formed earlier effectively partitions prior austenite grains into smaller separate regions. The bainite transformed at lower temperatures is thus restricted in the smaller regions so that fine-grained mixed microstructures are obtained. The superior toughness of the weld joint of the investigated steel is attributed to the prior formation of acicular ferrite in the heat-affected zone.
Evolution of Residual Stresses and Stored Elastic Energy in Ferritic Steel during Recovery Process
Authors: Wawszczak Roman , Baczmanski Andrzej , Braham Chedly , Seiler Wilfrid , Wróbel Mirosław , Wierzbanowski Krzysztof
Published: June 2010

Diffraction method was applied to determine the residual stresses in deformed and annealed polycrystalline samples of ferritic steel. The specific stored elastic energy corresponding to the grain stresses was calculated and presented in Euler space. An important decrease of the first and second order residual stresses and consequently stored elastic energy was observed during recovery and recrystallization. The evolution of stresses was correlated with the variation of diffraction peak width (related to dislocations density) and crystallographical texture.
Strain Measurement Near Fatigue Crack in Ultrafine-Grained Steel by Polychromatic Synchrotron Radiation
Authors: Akiniwa Yoshiaki , Kimura Hidehiko , Shibano Jyunichi , Kiriyama Koji , Shobu Takahisa
Published: June 2010

For engineering components with cracks, it is very important to evaluate the reliability for fracture. The X-ray diffraction method is now widely used to measure non-destructively the loading and residual stresses in crystalline materials. Synchrotron radiation sources provide the X-rays with extremely high intensity as well as a narrow divergence. The high intensity X-rays with a narrow divergence enables stress measurements in a localized region. The strain distribution near the fatigue crack in the steel plate with ultrafine-grained surface layers, called SUF plates, was measured by the polychromatic X-ray from synchrotron radiation at SPring-8. The spatial resolution in the direction parallel to the crack propagation direction was 0.1 mm. The strain distributions at several applied stress levels were determined for six diffraction planes. The measured strain distribution was compared with the result calculated by the FE analysis. The average value of the measured strains for several diffraction planes agreed well with the calculated results.
XRD Investigation of Residual Stresses in Electron Beam Deposited Pt-V Coatings
Authors: Ntsoane T.P. , Topic M. , Bucher R.
Published: June 2010

Platinum and platinum alloys, due to their good electrical and mechanical properties, are commonly used in fields such as jewellery, catalysis and electronics. In this work, a two-layer system of Pt and V, deposited on Si substrates by electron beam deposition technique, were investigated amongst others for residual stress development in the coating. The investigation was carried out using diffraction techniques employing laboratory X-rays on the BRUKER D8 Discover instrument equipped with a High Star detector and analyzed with LEPTOS v6 software. The results showed the stress state to be tensile, relaxing significantly on annealing. In addition, complementary results of phase composition, and coating morphology will also be presented.
Neutron Diffraction Residual Strain Measurements in Plasma Sprayed Nanostructured Hydroxyapatite Coatings for Orthopaedic Implants
Authors: Ahmed Rehan , Faisal Nadimul Haque , Knupfer Stefan M. , Paradowska Anna Maria , Fitzpatrick Michael E. , Khor Khiam Aik , Cizek Jan
Published: June 2010

Residual strains in plasma sprayed and heat-treated hydroxyapatite (HA) coatings deposited on a titanium alloy (Ti-6Al-4V) substrate were investigated by means of neutron diffraction. Strain measurements were performed in vertical scan (“z-scanning”) mode to provide a through thickness strain profile in the coating and substrate materials. Results are discussed in terms of the influence of heat-treatment on the residual strain profile of these biomedical coatings. This investigation concluded that the heat-treatment had a significant effect on the residual strain profile in HA coatings.
Residual Stress Evaluation of Carburized Transmission Steel Gear Using Neutron and Synchrotron X-Ray Diffraction and Finite Element Methods
Authors: Sakaida Yoshihisa , Serizawa Takanori , Kawauchi M. , Manzanka M.
Published: June 2010

A motorcycle transmission gear of chromium-molybdenum steel with 0.2%C was carburized in carrier gas. Carburizing process including heating, carburizing, diffusing and quenching was simulated using elastoplastic finite element method. The carbon content, hardness, residual strain and residual stress fields of gear were analyzed. The unstressed lattice plane spacing and residual strains of the interior near the internal spline of gear were experimentally measured by synchrotron x-ray and neutron diffraction methods. As a result, the analyzed carbon content and hardness gradients of gear accorded with the experimental results. The radial, hoop and axial directions of cylindrical gear were found to be not always principal axes of residual stress field. On the other hand, the analyzed residual strains in the radial, hoop and axial directions of gear slightly discorded with the experimental results. Although correlation between the measured three strains was similar to that of the weighted average of analyzed strains, residual strain and stress fields of motorcycle transmission gear could not be accurately predicted at the present finite element analysis. It was concluded that carbon diffusion phenomenon and resultant hardening could be analyzed by the finite element method, and the actual interior residual strain and stress fields should be nondestructively measured by neutron diffraction method.
Combined Neutron and X-Ray Diffraction Analysis for the Characterization of a Case Hardened Disc
Authors: Epp Jeremy , Hirsch Thomas , Hunkel Martin , Wimpory Robert C.
Published: June 2010

The present work has been executed within the framework of the collaborative research center on Distortion Engineering (SFB 570) in order to evaluate the residual stress state of a disc after carburizing and quenching as well as to validate a simulation procedure. The combined use of X-ray and neutron diffraction analysis provided information about the residual stress states in the whole cross section. However, the stress free lattice spacing d0 for the neutron diffraction experiments is problematic and induces systematic uncertainties in the results and the application of a force balance condition to recalculate d0 might be a solution for improving the reliability of the results. Comparison of experimental results with simulation showed that an overall satisfying agreement is reached but discrepancies are still present.
Numerical Modeling of Residual Stress and Prediction of Heat Affected Zone Induced by PTA Process
Authors: Nady Abdeljalil , Bonnefoy Herve , Klosek Vincent , Mathon Marie Helene , Lodini Alain
Published: June 2010

The objective of this study is to investigate the effects of Heat Affected Zone produced by Plasma Transferred Arc process and residual stress in substrate steel 55NiCrMoV7. In this study, based on ABAQUS code, a sequentially coupled thermal, metallurgical, mechanical 2-D finite element model is developed.
In the numerical simulations, the coating and Heat Affected Zone are used to predict the residual stresses. The simulation results revealed that the final residual stress in substrate steel do seem to be influenced by the HAZ.
Through-Thickness Residual Stress Measurement by Neutron Diffraction in Cu+W Plasma Spray Coatings
Authors: Luzin Vladimir , Matějíček Jiří , Gnäupel-Herold Thomas
Published: June 2010

A range of different spraying techniques can be used to coat the surfaces of engineering components. These techniques are based on different principles and can involve high temperature (plasma spray), high kinetic energy (cold spray) or both (HVOF spray – High-Velocity Oxi-Fuel). Resultant residual stress in such coatings, being a characteristic of the spraying process, can reveal details of the stress formation mechanism. When its dependence on the physical parameters and conditions of the spraying process is established, this knowledge can be used for the prediction and control of stress that occurs in applications. Neutron diffraction is a suitable method for obtaining stress distribution in such coatings.
Residual stresses in two-phase Cu+W coatings made by water stabilized plasma spraying were studied. Two-phase coatings develop both significant microstress (inter-phase stress) and the stress dependence on phase content of the coating constituents. Through-thickness residual stress profiles have been measured by neutron diffraction with spatial resolution of 0.5 mm for a series of Cu+W coatings with varying volume fractions. Measurements were made in both phases in order to separate micro- and macro-stresses. Comprehensive sample characterization, measurements of the residual stresses, mechanical and thermal properties of the composite coatings enabled quantitative modeling and interpretation of the experimental data.
Measuring Type II Stresses Using 3DXRD
Authors: Oddershede Jette , Schmidt Søren , Poulsen Henning Friis , Reimers Walter
Published: June 2010

An algorithm is presented for characterization of the grain resolved (type II) stress states in a polycrystalline sample based on monochromatic X-ray diffraction data. The algorithm is a robust 12-parameter-per-grain fit of the centre-of-mass grain positions, orientations and stress tensors including error estimation and outlier rejection. As examples of use results from two experiments – one on interstitial free (IF) steel and one on copper – will be presented. In the first experiment 96 grains in one layer of IF steel were monitored during elastic loading and unloading. Very consistent results were obtained, with resolutions for each grain of approximately 10 μm in position, 0.05˚ in orientation and 80 μstrain. When averaging over all grains a resolution of 10 μstrain was obtained. In the second experiment it was demonstrated that the strain states of more than 1000 grains in a plastically deformed Cu specimen could be determined to an accuracy of 100 μstrain.
Full Depth-Resolved Strain Mapping of a Three-Pass Slot Weld Specimen in Austenitic Stainless Steel Using the Spiral Slit Technique
Authors: Martins René V. , Ohms Carsten , Decroos Koenraad
Published: June 2010

An 18 mm thick three-pass slot weld specimen in austenitic stainless steel, manufactured for the purpose of benchmarking Finite Element weld residual stress simulation codes, is currently undergoing extensive non-destructive characterization within a research network. First results from the non-destructive full three dimensional spatially resolved macro-strain mapping in this specimen are presented here. Focussed high-energy synchrotron radiation together with the spiral slit technique was used to obtain depth-resolved information about the variation of lattice parameters. The results show a strong concentration of tensile strain, transverse to the weld at mid-depth of the weld. The maximum longitudinal strains were observed beneath the weld. Furthermore significant weld start- and stop-effects were observed.