bluuebunny/crossref_metadata_2025 huggingface dataset:
Microstructure and Tensile Properties of Oxide Dispersion Strengthened Molybdenum Alloys Prepared by Different Doping Process
Authors: Sun Yuan Jun , Zhang Guo Jun , Zuo Chao , Wei Jian Feng , Sun J.
Published: March 2009

The oxide lanthanum dispersion strengthened molybdenum alloys were prepared by
proprietary powder metallurgy technology, in which the Mo-La2O3 powders were prepared by
liquid-liquid doping process which the oxide lanthanum was added to ammonium bi-molybdate
solutions as aqueous solutions of La(NO3)3 and liquid-solid doping process which the oxide
lanthanum was added to molybdenum oxide solid particles as aqueous solutions of La(NO3)3,
respectively. The microstructure and tensile properties of the molybdenum alloys were investigated at
room temperature. The results show that the molybdenum alloys all have fine molybdenum grains,
and the molybdenum alloy prepared by liquid-solid doping process mainly contain fine oxide
lanthanum particles of submicron and nano-sized while the alloy prepared by liquid-liquid doping
process mainly contain nano-sized fine oxide lanthanum particles. The molybdenum alloys prepared
by liquid-liquid doping process have higher yield strength and ductility than yield-solid doping
process. The results of strengthen mechanism analysis show that the high strength of the
molybdenum alloys can be advisablely explained by the fine grain strengthening and particles
dispersion strengthening mechanism through the Hall–Petch relationship and Orowan model.
Welding Characteristic Evaluation of GMAW and Laser Cladding for the Gas Turbine 1st Blade
Authors: Kim Hyung Ick , Park Hong Sun , Koo Jae Mean , Yang Sung Ho , Kim Moon Young , Seok Chang Sung
Published: March 2009

The advancement in superalloys permits the hot gas path components to operate for
thousands of hours under severe centrifugal, thermal and vibratory stresses. The blade of a gas turbine
must withstand the most severe condition combined of temperature, stress, and environment. After a
long operation, the damaged blades of a gas turbine used are welded for build-up and repaired. We
analyzed and compared the mechanical properties of GMAW(Gas Metal Arc Welding), a manual
welding method, a laser cladding method, and an automatic welding method under research and
development.
A Study on the Degradation of the Superalloy Inconel 718 Using Ultrasonic Technique
Authors: Park Hong Sun , Kim Hyung Ick , Huh Yong , Kim Moon Young , Park Sang Yeol , Koo Jae Mean , Seok Chang Sung
Published: March 2009

The Ni-based superalloy Inconel 718 (IN-718) was developed in the 1950s and is currently
used for several critical gas turbine components due to its good balance of mechanical properties.
Because of its stable mechanical properties at high temperature, the alloy is used for turbine bolts. The
mechanical properties of in-service facilities are required to maintain safety operation in power
plants. Ultrasonic tests, tensile tests and hardness tests were performed to evaluate the degree of the
material degradation of Inconel 718. The mechanical properties decreased as degraded, but the
longitudinal velocity of the ultrasonic signal increased. Also, the microstructure of the degraded
Inconel 718 was to study the relationship between the result from ultrasonic test and the results from
destructive methods.
Study on Impact Fatigue Life of 42CrMo Steel with M+F Dual-Phase Structure
Authors: He Bo Lin , Yu Ying Xia , Shao Er Yu
Published: March 2009

The effect of undissolved ferrite amount on impact fatigue properties and failure mechanism
were studied by using 42CrMo steel with subcritical quenching process The amount of undissolved
ferrite were 0%, 10% and 15%, respectively. The experimental results show that the existence of
undissolved ferrite can not only change the microstructure, but also increase the impact fatigue life The
impact fatigue life elongates with increasing of amounts of undissolved ferrite The grain can be fined by
using subcritical quenching process and the area of phase boundaries can also be greatly increased
because of undissolved spheroidal carbide. The martensite and carbide form can also be changed by
using subcritical quenching process The stress relaxation due to the moving of dislocations inside the
ferrite and the promotion of strength due to occurring of plastic deformation and the enwinded
dislocations are main reasons of improving the impact fatigue life. The impact fatigue life elongates
with the increase of amounts of undissolved ferrite before the amount of undissolved ferrite reaches 10%.
Under the experiment conditions, when the amount of undissolved ferrite is 10%, the impact fatigue life
will be the longest.
Effect of Plastic Deformation at Room Temperature on Powder RE-Chrome-Boronizing for Medium Carbon Steel
Authors: Xu Bin , Yang Le , Xing Shi Bo , Li Li
Published: March 2009

In order to increase boronizing speed without decreasing the hardness of boride layer, the
effect of plastic deformation at room temperature on powder RE-chrome-boronizing for a medium
carbon steel (steel 45), in which boronizing plays a main role, was studied in this paper. The cold
plastic deformation (CPD), whether compressing or shot-peening, can increase boronizing speed.
Meanwhile, the boride layer can also retain its high microhardness (1 300―1 900HV0.1) with low
brittleness. The layer depth achieved for a given heating time increases with increasing CPD degree
on the steel. The analyses show that boronizing kinetics in the RE-chrome-boronizing (RE-Cr-B)
samples with CPD can be enhanced.
Long Wavelength Buckling of Cubic Open-Cell Foams Subjected to Uniaxial Compression
Authors: Okumura Dai , Okada Atsushi , Ohno Nobutada
Published: March 2009

In this study, the elastic buckling strength of cubic open-cell foams subjected to uniaxial
compression is investigated using the homogenization framework developed by the present authors
(Ohno et al., JMPS 2002; Okumura et al., JMPS 2004). First of all, based on the framework, the
microscopic bifurcation and macroscopic instability of cubic open-cell foams are numerically
analyzed by performing finite element analysis. It is thus shown that long wavelength buckling is the
primary mode and occurs just after the onset of macroscopic instability. Then, a solution for
predicting the stress of long wavelength buckling is analytically derived from the onset condition of
macroscopic instability. The validity of this analytical solution is demonstrated by the finite element
results.
Failure Analysis of Al1060 Sheets under Double-Sided Pressure Deformation Conditions
Authors: Wang Zhong Jin , Wang Zhe , Li Min Xing
Published: March 2009

The viscous pressure bulge (VPB) testes of the aluminum Al1060 sheet were carried out
with stainless steel overlapped outside without lubricant. The influence of the compressive normal
stress on the failure behavior of aluminum sheet was investigated by scanning electron microscope
observations. The results indicate that the forming limit of overlapped aluminum sheet is increased
significantly compared with the single aluminum sheet. Fractography shows that the void growth
and conjunction in the thickness direction is restrained by normal pressure and the fracture mode of
overlapped sheet transits from the dimple fracture to shear fracture due to the reduction of stress
triaxiality.
Surface Morphological Changes in CP-Ti and SUS316L under Pure Tensile Loading and Creep
Authors: Mayama Tsuyoshi , Sasakir Katsuhiko , Narita Yoshihiro
Published: March 2009

The present paper investigates relationships between the macroscopic viscoplasticity and
the surface morphological changes at room temperature for commercially pure titanium (CP-Ti) and
austenitic stainless steel (SUS316L). Pure tensile test and tension-intermittent creep test are
conducted. Both CP-Ti and SUS316L are deformed up to 16% of inelastic strain with a few unloading,
and surface conditions are observed during pure tension test and tension-intermittent creep test.
Qualitative surface observations and quantitative surface roughness measurements are made for the
unloaded specimens. The surface roughness measurement shows that the curves plotted between
surface roughness and inelastic strains are almost linear for all the present experiments. The slopes of
curves depend, however, on material and type of tests, and this tendency agrees well with the
qualitative surface observations by an optical microscope. The experimental results for CP-Ti suggest
that different deformation mechanisms during tensile loading and creep contribute to different surface
morphological changes.
Development of Constitutive Equation for Infinite Body of Impact Problem
Authors: Yang Seung Yong
Published: March 2009

A constitutive equation was developed for an infinite body in plane wave impact problem,
and implemented using the finite element software ABAQUS user subroutine. Bilinear material
behavior under monotonically increasing loading was considered for the constitutive equation. The
finite element governed by this type of material behavior can be used as an infinite body
transmitting longitudinal and shear plane waves, so that the number of finite elements can be
reduced in impact simulations. To test the developed method, results of a plate impact experiment
were examined. The numerical results show the accuracy of the developed constitutive equation.
EBSD Analysis and Theoretical Prediction of Twin Orientations during Compression in Mg-3Al-1Zn
Authors: Jiang Jia , Godfrey Andrew , Liu Qing
Published: March 2009

In order to improve the formability of magnesium alloys at low temperatures, a thorough
understanding of the twinning behaviour is required. Cylindrical samples were compressed uniaxially
from room temperature to 250oC, with the compression axis parallel to the transverse direction (TD)
of a hot-rolled Mg-3Al-1Zn sheet. Twinning was investigated by use of orientation maps constructed
from electron backscattered diffraction (EBSD) data. Tensile twinning was observed at all
temperatures. In some grains two twin variants were observed. For each twin the specific twinning
variant among the 6 possible twinning systems was identified by consideration of the twinning
rotation. The twinning was then investigated by comparing the specific twin variant with the
calculated Schmid factors for all 6 possible twin variants. In cases of grains that are completely
reoriented by two twin variants it is possible to back-calculate the initial grain orientation by
considering all possible twin rotations for both of the twin variants. It was found that the operative
twin variants where those with the highest Schmid factors.
Compressive Deformation in Aluminum Foam Investigated Using a 2D Object Oriented Finite Element Modeling Approach
Authors: Adziman M.F. , Deshpande S. , Omiya Masaki , Inoue Hirotsugu , Kishimoto Kikuo
Published: March 2009

The stochastic nature of aluminum foam structure, having a random distribution of voids,
makes it difficult to model its compressive deformation behavior accurately. In this paper, a
2-dimensional simplified modeling approach is introduced to analyze the compressive deformation
behavior that occurs in Alporas aluminum foam (Al foam). This has been achieved using image
analysis on real undeformed aluminum foam images obtained by VHX-100 digital microscope. Finite
element mesh for the cross sectional model is generated with Object Oriented Finite element (OOF)
method combined with ABAQUS structural analysis. It is expected that OOF modeling enable
prediction of the origin of failure in terms of localized deformation with respect to the microstructural
details. Furthermore, strain concentration sites leading to the evolution of the deformation band can
be visualized. Thus, this investigation addresses the local inhomogeneity in the Al foam structure.
This study implies that the OOF modeling approach combined with experimental observations can
provide better insight into the understanding of aluminum foam compressive deformation behavior.
Acoustic Emission Investigation of the Anelastic Recovery Behavior of Basal Plane Textured AZ31B as a Function of Loading Direction
Authors: Li Yun Ping , Enoki Manabu
Published: March 2009

In order to study the texture effects on the anelastic recovery behavior of magnesium
alloy, basal plane textured AZ31B alloy was compressed parallel and vertical to the extrusion
direction. AE measurement was applied to characterize the deformation and the anelastic recovery
behaviors. A model for the correlation between applied strain and the cumulative AE counts in
detwinning was proposed. The effects of loading direction to the deformation and twinning
behavior were discussed.
Deformation Behavior and Strength of Beam-To-Column Connections in Steel Portal Frame
Authors: Kim Young Moon , Yang Cheol Min , Ko Nag Ho , Hong Dong Pyo
Published: March 2009

This paper presents an experimental work on the cyclic behavior of bolted and welded
beam-to-column connections in steel portal frame. Three types of connection were used; tests for
each specimen were performed twice in order to maintain test reliability. Specimen 1 (DWA) had
only a double web angle connection, specimen 2 (TSD) had a top and seat angles with double web
angle connection, and specimen 3 (FW) had a fully welded connection. All specimens were tested
under cyclic loading conditions in order to simulate the effects of earthquakes. We also conclude
that with appropriate design and careful consideration of connection strength and stiffness, the steel
project economy may be maximized.
Research on Hot Upsetting Deformation Behavior and Dynamic Recrystallization for AZ31
Authors: Hu Wei Hui , Liu Tian Mo , Liu Qing
Published: March 2009

The AZ31 Mg alloy was upseted from 250°C to 500°C. In optical microscopy, as the
temperature increases, the volume fraction of deformation twin will reduce to a minium and vanish.
Simultaneously, some small dynamically recrystallized grains were observed at the boundaries of
origin grains and twins. When temperatures rise from 350°C to 500°C , the volume fraction and size
of DRX grains increases .By the compression test of the upsetting proof samples, the compressive
strength reach a maxium, and reduce during further rising temperatures.
The Application of Wavelet Theory in Analysis of Surface Topography of Rifle Worn Marks
Authors: Wang Bing Cheng , Jing Chang , Ren Zhao Hui , Song Nai Hui
Published: March 2009

This paper makes decomposition of the profile curve of rifle worn marks by the wavelet
transform, which can make its complicated structure feature to be clear. By reconstruction, the noise
in the process of collecting and distraction can be removed, which makes the calculated fractal
dimension more reliable. The research shows that wavelet transforms of profile curves can not only
describe the surface topography of rifle worn marks, but also exhibits its essence characteristics.
The paper provides a new method of quantitative examination and classification identification for
rifle worn marks.
Friction Characteristics between Two Bodies under the Vibration Working Condition and their Applications
Authors: Wen Bang Chun , Li He , Ren Zhao Hui , Han Qing Kai , Liu Jie
Published: March 2009

This paper mainly focus on vibration friction and discuss the dynamic characteristics of
the friction under the vibration working condition. It is rather valuable to study such a special kind
of friction vibration in engineering. Many practical projects have already proved that under the
vibration working condition, the friction force between workpieces can be reduced obviously. Wear
and damage of the machine parts can be obviously decreaed.The work efficiency can be improved
greatly. The Characteristic of friction under the vibration working condition is described in the
paper firstly. Two fundamental experiments illustrate the basic features of vibration friction. With
the nonlinear dynamics and tribology of vibration friction, some key machinery is introduced in the
paper briefly. The study of vibration tribology is attracting more and more interest of investigators.
Wear Mechanism of Ti(C, N)-Based Cermet Cutting Tools in the Machining of Normalized Medium Carbon Steel AISI1045
Authors: Shi Zeng Min , Zheng Yong , Liu Wen Jun
Published: March 2009

Ti(C, N)-based cermet cutting tools were prepared by vacuum sintering and tested in dry
machining of normalized medium carbon steel (AISI1045) at various combinations of cutting speed
(Vc), feed rate (f), and depth of cut (ap). And the wear mechanism was investigated in detail using
scanning electron microscopy (SEM) and electron-probe microanalysis (EPMA). Comparing to the
cemented carbide YT15 and cermet TN20, the newly fabricated cermet tools exhibited better
performance and higher wear resistance. For Ti(C, N)-based cermet tools, the wear mechanism was
predominantly controlled by the flank wear under all cutting condition. It was found that the
removal of the ceramic grain and abrasive wear were the main source of tools failure. In addition,
adhesion and oxidation were also observed.
Unequal Interval Grey Forecast of the Rate of High Temperature Abrasion of Water-Wall Tubes in Circulating Fluidized Bed Boilers
Authors: Deng Hua Ling , Wang Yong , Zhao Hong
Published: March 2009

An unequal interval grey forecast model GM (1, 1) was proposed based on the grey
system theory and the measurement data of the rate of high temperature abrasion of water-wall
tubes in circulating fluidized bed (CFB) boilers. According to the former part of measurement data,
the latter part of high temperature abrasion rate of water-wall tubes was forecasted by using the GM
(1, 1) model. Through comparing the computation values with the measurement values, the
accuracy and the feasibility of the model were verified. The result shows that under small statistics
conditions, the unequal interval grey forecast model can offer precisely prediction results, which can
provide scientific basis and guidance for the condition-based maintenance of the water-wall tubes in
CFB boilers.
Research on Nano-Mechanical and Micro-Tribological Behaviors of C+- Implanted Silicon
Authors: Zhang De Kun , Wang Qing Liang , Wang Shi Bo
Published: March 2009

The knowledge of tribological properties of silicon is important due to its potential
application for micromechanical devices. Single crystal silicon wafers were implanted by carbon
ion with an energy of 80 keV and different implantation doses of 2×1015 ions/cm2 and 2×1016
ions/cm2, respectively. The nanohardness and elastic modulus of silicon wafers before and after C+
implantation were studied on the nano-mechanical testing system. The micro sliding tests on silicon
wafers before and after C+ implantation were performed on the UMT-2 Micro-tribometer to
investigate the coefficient of friction and wear volume. The results demonstrate that the
nanohardness and elastic modulus of silicon wafer at the implantation dose of 2×1015 ions/cm2
decrease and those of 2×1016 ions/cm2 have little change. C+ implantation improves
friction-reducing effect of silicon wafers and the coefficient of friction decreases to a great extent.
But when the load reaches a certain value, the coefficient of friction increases sharply and the worn
trace occurs on the silicon surface. Adhesive and abrasive wear are the main mechanisms at light
loads and micro fatigue is the main mechanism at heavy loads.
A New Model of Stochastic Crack Growth under Random Loading and Reliability Analysis of Fatigue Life
Authors: Huang Hong Zhong , Huang G. , Miao Qiang , Ling Dan , Ma Q.
Published: March 2009

A new model is proposed for the analysis of fatigue crack growth under random loading.
The fatigue rule of crack length is transformed into the monotony function rule based on types of the
crack. By performing reliability analysis, the randomness of the stress, the stochastic nature of the
crack growth, the fuzziness of the initial crack size and the randomness of the crack critical size are
considered. The First-order-second-moment approximation method is used to obtain the solution of
the probability density function. An example is given to illustrate feasibility of the proposed method.
Tribological Behaviors of Bulk Metallic Glasses
Authors: Kong Jian , Xiong Dang Sheng , Fan Xin Min , Li Jian Liang , Yuan Qun Xing
Published: March 2009

The tribological properties of Zr-based and Cu-based bulk metallic glasses (BMGs) sliding
against discs of SUS 304 and Si3N4 at room temperature under dry and lubrication of fresh plasma,
distilled water, and physiological distilled water were investigated on a pin-on-disc testing machine. The
results demonstrated the influences of counterface materials, lubrication conditions and the characteristics
of BMGs on the frictional behaviors of the Cu- and Zr-based BMGs. It is found that the steady state
friction coefficients and the wear rates sometimes are not consistent, and the wear resistance was been
improved when the counterface change from SUS304 to Si3N4. Otherwise, wear rates of the BMGs under
lubrication conditions are much lower than that of under dry sliding conditions, and the Cu-based BMGs
exhibits higher wear resistance than Zr-based BMGs under same experimental conditions because it is a
nanocrystalline amorphous alloy and has the higher glass transition and crystallization temperatures.
Fracture Healing in the Presence of Polyethylene Wear Debris and Oestrogen Deficiency
Authors: Oliver Rema , Yee G. , Yu Y. , Matthews J.B. , Ingham E. , Walsh W.R.
Published: March 2009

The number of peri-prosthetic femoral fractures in todays aging population is increasing.
Fractures of the femur may occur intra-operatively or post-operatively, either at the tip of the femoral
stem or in areas where cortical thinning has occurred. This is further enhanced if the patient is
osteoporotic. These fractures can be difficult to treat due to the complexity of the mechanical status
and further complicated biologically by the presence of ultra high molecular weight polyethylene
(UHMWPE) wear debris that can migrate from the articulating surface of the prosthesis to the fracture
site. In this study, the effect of PE wear debris on the healing of osteoporotic fractures was
investigated using a rodent ovariectomised (OVX) model.
One hundred female Sprague Dawley rats were subjected to either bilateral OVX or Sham surgery
at 10 weeks of age. Three months later, a closed fracture was created in the right femur using a 3-point
bending device and an intramedullary k-wire for fixation. Animals were divided into 4 groups
(n=3-8). A 0.2ml suspension of Ceridust (PE wear debris), hyaluronic acid & saline was injected
directly into the fracture site at the time of surgery into half the animals. Control animals received
comparable injections excluding the Ceridust. Animals were sacrificed at 1, 3 and 6 weeks.
The OVX animals had a greater body weight compared to the Sham animals (p<0.05). DEXA
analysis revealed that the presence of PE wear debris had no effect on the BMD within the fracture
callus at either time-point. Mechanical analysis revealed an increase in bone strength with time. The
presence of PE had no statistical effect upon the ultimate peak load or stiffness, however there was a
trend towards increased peak load in the PE groups at 3 and 6 weeks following 3-months oestrogen
deficiency. Histological analysis showed that the control OVX fractures had more cartilage
development than the Sham group at 3 weeks and delayed remodeling at 6 weeks. The PE treated
OVX group showed more fibrous tissue at the fracture gap and inside the diaphysis tunnel showing
further delayed healing compared to the Sham group with PE.
In this study after 3-months of oestrogen deficiency, no differences in mechanical or BMD was
found in the fractured limbs between the PE –treated and non-PE treated fractures. However,
histologically, PE wear debris induced fibrous tissue at the fracture site which further delayed the
healing process. More care should be taken with aged patients receiving revision surgery, as these
patients become harder to manage when fractured due to the influence of both osteoporosis and PE
wear debris.
Sliding Wear Behavior of Al/SiC Composites Fabricated by Thermal Spray Process Against Different Counterparts
Authors: Kim Yeong Sik , Kim Kyun Tak , Kim Seon Jin
Published: March 2009

SiC particulates reinforced Al matrix composites were fabricated by thermal spray process,
and the dry sliding wear behavior against four different counterparts was investigated under a varying
of the sliding speed and the applied load conditions. Al/SiC composites were fabricated by flame
spraying, and the dry sliding wear tests were performed using the sliding speed of 0.4 m/s and 0.8 m/s
at the applied load of 3 N. Sliding distance was kept at 1000 m for all the tests. Al2O3, ZrO2, Si3N4 and
AISI 52100 balls were used as the counterparts. Wear tracks on the Al/SiC composites were
investigated using scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy
(EDX). It was revealed that wear behavior of Al/SiC composites was much influenced by counterpart
materials.
Effect of Stress Relief Groove Shape on Fretting Fatigue Strength
Authors: Kataoka Shunsuke , Sakae Chu , Kubota Masanobu , Kondo Yoshiyuki
Published: March 2009

The objective of this study is to evaluate the effect of stress relief groove on fretting
fatigue strength. Fretting fatigue tests and finite element analyses were done. The shape of groove
was controlled by groove radius R and tangential angle θ. The depth of groove was specified by R
and θ. Fretting fatigue strength was increased with an increase of θ and then it turned into a
decrease. The decrease was caused by the transition of failure mode from fretting fatigue at the
contact part to plain fatigue at the groove root. The transition was caused by an increase of stress
concentration at the groove root with an increase of the groove depth. Therefore, the maximum
improvement of fatigue strength was achieved by the largest θ limited by fatigue strength of the
groove root. In the analysis, the groove generates high compressive stress field at the contact edge,
where small cracks never propagate. Therefore, assumptions to relieve the contact pressure
concentration at the contact edge were taken into the analysis model. The values of stress intensity
factor ranges for small cracks introduced near the contact edge were almost the same between
grooved and non-groove specimens.
Tribological Behaviour of Ceramic Coatings Formed on Titanium Alloy through Miro-Arc Oxidation Technique
Authors: Sun Xue Tong , Lin Cheng Xin
Published: March 2009

In the present work, the wear behaviour of coatings produced on Ti-6Al-4V alloy by
micro-arc oxidation method was studied. The wear tests were performed using a pin-on-disc wear
machine under dry sliding conditions. It is found that the MAO coating can efficiently improve the
wear-resistant performance of Ti alloy in the test range of this paper. The coated samples
demonstrated wear rates up to 5-12 times lower than that of the uncoated substrates tested. The
wear behaviours are deeply characterized by the variations of coating structure and composition.
Metal Working and Dislocation Structures
Authors: Hansen Niels
Published: March 2009

Microstructural observations are presented for different metals deformed from low to
high strain by both traditional and new metal working processes. It is shown that deformation
induced dislocation structures can be interpreted and analyzed within a common framework of grain
subdivision on a finer and finer scale down to the nanometer dimension, which can be reached at
ultrahigh strains. It is demonstrated that classical materials science and engineering principles apply
from the largest to the smallest structural scale but also that new and unexpected structures and
properties characterize metals with structures on the scale from about 10 nm to 1 μm.
Three Dimensional Numerical Approach to Splitting Failure of Rock Discs
Authors: Xu Tao , Ma Tian Hui , Tang Chun An , Liang Zheng Zhao
Published: March 2009

The Brazilian splitting tests have been commonly and widely used as a standardized test
method on disc or cylinder specimens to measure the indirect tensile strength of rocks in mining
engineering and other rock engineering. In this paper, a novel numerical code, 3D Rock Failure
Process Analysis code, was applied to implement the splitting tensile failure tests on rock discs. The
influences of the heterogeneity on stress distribution in rock are also discussed and the splitting failure
patterns of specimens subjected to Brazilian tests are simulated. The simulated splitting results of
rock discs were found quite realistic, which indicate that the rock failure analysis method is applicable
and practical for the study of rock disc splitting failure.
Effect of High Tensile Pre-Strain on the Torsional Fatigue Properties of a Structural Steel
Authors: Zhou Cong Ling , Nishida Shinichi , Hattori Nobusuke
Published: March 2009

This study is developed to investigate the effect of monotonic plastic deformation on the torsional fatigue properties of a structural steel. Five different kinds of tensile pre-strain, 2%, 5%, 8%, 12% and 22%, were applied to the specimens, respectively. And the maximum pre-strain value is near to the necking strain of the test material. The effects of tensile pre-strain on surface hardness, fatigue crack initiation and propagation behaviors, and the behavior of non-propagating cracks. The main results obtained are: The fatigue limits are 145, 160,175, 200 and 215MPa for specimens with tensile pre-strain of 2% 5%, 8%, 12% and 22%, which are improved to 104%, 114%, 125%, 143% and 153% of the fatigue limit for non-pre-strained specimens, respectively. The torsional fatigue limit increases with the tensile pre-strain increasing, until the pre-strain value being near to the necking strain ratio. However, the fatigue limit increase becomes more slowly for high tensile pre-strained specimens than the lower ones. The fatigue cracks of the tensile pre-strained specimens initiated earlier than that of the non-pre-strained specimens, and the propagation is also accelerated, but there is no effect on the fatigue crack initiation point and the branch point. Non-propagating crack length becomes shorter with increasing of tensile pre-strain until the value near the necking strain, and the quantity of non-propagating crack increases at the same time.
Atomistic Finite Element Simulations on the Tensile Properties of Polyhedral Oligomeric Silsesquioxane (POSS) Reinforced Polystyrene
Authors: Zeng Fan Lin , Sun Yi
Published: March 2009

The influences of the polyhedral oligomeric silsesquioxane (POSS) on the mechanical
properties of the polystyrene (PS) under tensile strain loading were studied using the atomistic finite
element simulations. Firstly, the nano scale pole-like atomistic models and the micro scale pole-like
finite element models of two kinds of homopolymers, the pure PS and the polystyrene attached with 5
mol% propyl-POSS (P-POSS-PS), were built, after which the atomistic finite element models were
built by connecting the carbon and silicon atoms on the boundaries of the atomistic models to the
corresponding nodes in the finite element ones. Then the mechanical behaviors of the two kinds of
homopolymers under different tensile strains were investigated. The results show that, when the
tensile strain of PS reaches 0.05 the micro voids appear. The tensile stresses of PS approximatively
keep increasing with the increasing strain before the tensile strain of 0.07, after which the stresses
declines. And the corresponding tensile modulus of PS is 4.52GPa. By contrast with PS, when the
tensile strain of P-POSS-PS reaches 0.06 the micro voids appear. The tensile stresses of P-POSS-PS
are almost keeping increasing before the tensile strain of 0.08, and the corresponding tensile modulus
is 5.32GPa. Conclusions can be made from this work that the tensile strength of homopolymers can be
observably improved by POSS. A small quantity of POSS can even improve the toughness of
homopolymers slightly. This work has realistic theoretical significance to understand the
reinforcement mechanism of POSS and provides important referential message to the applications of
POSS.
Study on the Modelling of Microstructure for Polycrystalline Materials
Authors: Xu Yan Hai , Guo Li , Li Hao
Published: March 2009

Microstructure plays a significant role in the evolution of short fatigue cracks. The
modelling procedure of microstructure for polycrystalline materials is presented in this paper. The
factors that effect on the modelling of microstructure are discussed in detail. Firstly, the 2D
microstructure of LZ 50 steel with straight grain boundary is simulated with the help of Voronoi
tessellation. To validate the modelling results of the microstructure, two load cases are intentionally
designed to verify the microstructure for the view of comparing the results with homogeneous
material under the same load cases. The whole process is carried out with the application of FEM.
From the comparison of mechanical properties generated by the simulated microstructure with
anisotropic material property to the ones showed by macrostructure with homogeneous material
property, the validity and convenience of the modelling process is shown. The simulated
microstructure for polycrystalline materials can be used for the further research on the initiation and
growth of short fatigue cracks.
Research on Micro-Mechanism of Nanocomposite Ceramic in Two-Dimensional Ultrasound Grinding
Authors: Zhao Bo , Wu Yan , Gao Guo Fu , Jiao Feng
Published: March 2009

Surface microstructure of nano-composite ceramics prepared by mixed coherence system
and machined by two-dimensional ultrasonic precision grinding was researched using TEM, SEM,
XRD detector and other equipments. Structure, formation mechanism and characteristic of
metamorphic layer of ground surface of nano-composite ceramics were researched. The experiment
shows micro deformation mechanism of ceramic material in two-dimensional ultrasound grinding is
twin grain boundary and grain-boundary sliding for Al2O3, and it is crystal dislocation of enhanced
phase, matrix grain boundary sliding, coordination deformation of intergranular second phase as well
as its deformation mechanism for nano-composite ceramics. The fracture surfaces of nano-composite
materials with different microscopic structure were observed using TEM and SEM. Research shows
that ZrO2 plays an important influence on the generation and expansion of crack, and enhances the
strength of grain boundaries. When grain boundaries is rich in the ZrO2 particles, the crack produced
in grinding process will be prevented, and the surface with plastic deformation will be smooth. The
results shows nanoparticles dispersed in grain boundary prevents crack propagation and makes
materials fracture transgranularly which makes the processed surface fine.
Electrochemical Grinding for Unclosed Internal Cylinder Surface
Authors: Ming Ping Mei , Zhu Di , Xu Zheng Yang
Published: March 2009

The electro discharge machining (EDM) process is widely applied to produces surfaces of difficult-to-machine materials that require some form of grinding or finishing operation. This is conducted so as to improve the surface texture and appearance of the component’s surface. However, it is also desirable to remove the white uppermost recast layer or damaged surface layer (produced by the EDM process) in order to improve the functional performance of the surface. The finishing of the surface by traditional manual methods, especially in the operation of small and long internal cylinder surface, is both tedious and time-consuming. A novel electrically conductive diamond mounted point electrochemical grinding (DMP-ECG) process is being developed for hard passive alloys unclosed internal cylinder surface grinding. The process mechanism of DMP-ECG is introduced; the influence parameters of the surface roughness, machining accuracy, and diamond tool wear are investigated experimentally for nickel-based super alloys materials. An application of the DMP-ECG to aircraft engine component is verified in term of the optimized process parameters.
Surface Waviness Analysis for Axisymmetric Aspheric Lens in Precision Grinding
Authors: Wang Zhen Zhong , Guo Yin Biao
Published: March 2009

For precision grinding, especially the aspheric grinding, the vibrations of wheel and
workpiece have great impact on workpiece accuracy and roughness with special waviness. This
paper firstly studies the relationship between grinding parameters and surface quality. Then
according to the two kinds of aspheric machining mode: grinding with equal step feeding and
grinding with equal angle feeding, the corresponding surface equations and vibration equations after
grinding are given in this paper. Moreover, the specific analysis of aspheric surface model and
surface waviness are also discussed for parameters optimization. The grinding experiments are done
to support the theoretical research. The comparison between theoretical waviness analysis and
experimental results shows good matching.
Experimental Study on Porous Metal Bonded Diamond Grinding Wheels (II) ─ Grinding Performance of Porous Wheels
Authors: Dai Qiu Lian , Luo Can Bin , Liao Cui Jiao
Published: March 2009

In this paper, two metal-bonded diamond wheels with different porosity were fabricated.
The porosity of diamond wheel without additives of pore inducers is 7% and the wheel with pore
inducers is 38%. Grinding experiments with these two grinding wheels on marbles were carried out
under different grinding conditions. Experimental results revealed that highly porous grinding
wheel has smaller grinding forces and better self-sharpening ability than the compact grinding
wheel under the same grinding conditions.
Research on Interfacial Microstructure of Ti-Coated Diamond Brazed and Uncoated Diamond Brazed by High-Frequency Induction
Authors: Ma Bo Jiang , Fu Yu Can , Ding Wen Feng , Gao Wei , Xu Hong Jun
Published: March 2009

The Ti-coated diamond and the uncoated diamond were brazed with Ni-based filler alloy by high-frequency induction under argon atmosphere at 1050°C within 15 seconds. The interfacial microstructures between brazed diamond and the filler alloy were analyzed by scanning electron microscopy (SEM), energy dispersion spectrometer (EDS) and X-ray diffraction (XRD). It is surprisedly found that Cr-carbides forms normally and compactly on the surface of Ti-coated diamond brazed, whereas Cr-carbide forms tangentially and loosely on the surface of uncoated diamond brazed. The abrade experiment results for the brazed diamonds show that the bond strength between the normally formed Cr-carbide and the diamond is higher than that between Cr-carbide and uncoated diamond brazed. Furthermore, the cause that Ti changes the morphology of Cr-carbides on the surface of Ti-coated diamond brazed is discussed by the further tests specially designed.
Study on a Grinding Quality Assessing Method Based on Fuzzy Decision Combined with Analytic Hierarchy Process (AHP)
Authors: Shi Xiao Long , Liu Gui Jie , Wang Qiang , Kang Ren Ke
Published: March 2009

The grinding quality assessing is a complex decision-making process, which must optimize and balance multi-influence factors. A grinding quality assessing method based on fuzzy synthetic evaluation theory combined with analytic hierarchy process (AHP) is presented in this paper, and used to quality assessing for grinding process. The result of analyzing example indicates that this method can be used to estimate grinding quality based on the monitoring result of grinding process and grinding condition, and to assist grinding worker to select optimum grinding parameters for the steady grinding quality.
Formation and Control of Burr in Grind-Hardening
Authors: Wang Gui Cheng , Liu Ju Dong , Li Qin Feng , Zhu Yun Ming , Pei Hong Jie , Zhang Jin Yu
Published: March 2009

Based on grind-hardening experiments, the two side-direction burrs were studied. Three
main stages (burr generation, augmentation and formation) in the burr yielding process were clarified
and the varying laws of burr morphologies and dimensions were systematically revealed. In turn
raises, some new technologies, processes and methods of actively controlling burrs were put forward.
Cellular Responses of MC3T3-E1 Mouse Osteoblast-Like Cells to Rough Surfaced Substrates
Authors: Saito Takao , Hayashi Hikoshiro , Kameyama Tetsuya , Kato Katsuya
Published: March 2009

MC3T3-E1 mouse osteoblast-like cells were seeded at high cell density to form confluent
monolayer on rough surfaced culture substrates. Osteoblastic gene and protein expressions and
matrix mineralization were investigated to clarify the effect of surface roughness on differentiation
of MC3T3-E1 cells.
Impact of Calcium Phosphate Particle Morphology on Osteoconduction: an In Vivo Study
Authors: Drouet Christophe , Barré Ronan , Brunel Gérard , Dechambre Gérard , Benqué Edmond , Combes Christèle , Rey Christian
Published: March 2009

Apatite/β−TCP particles exhibiting non-conventional urchin-like morphology were prepared by hydrothermal synthesis. Their implantation in the rat calvarium was followed during 60 days. A total absence of osteoconduction was observed despite a favorable chemical composition, stressing the fundamental role of particle morphology on bone regeneration. Results are discussed in relation with other literature data. Possible explanations include the disfavored accumulation of biological mediators due to the acicular shape of the particles and/or a limited accessibility for cells.
Comparison of New Bone Formation and Osteotomy Speed in the Rabbit Mandible Using Piezoelectric Surgery and Conventional Burs
Authors: Yun K.H. , Kim S.G. , Lim Sung Chul
Published: March 2009

We compared the effect of osteotomies performed using piezoelectric surgery
(Piezosurgery®) and the conventional bur method on new bone formation in the rabbit mandible,
focusing on light-microscopy observations of the early healing process after 1, 2, and 4 weeks. The
time required to perform the osteotomy was also compared. We showed that piezoelectric surgery
and the conventional bur method had no marked difference on early bone healing, although the
osteotomy time was shorter with the conventional bur method than with Piezosurgery. Because the
instrument used in Piezosurgery is sharp and more controllable, piezoelectric surgery should be
more useful for delicate surgery, such as maxillary sinus lifting and segmental osteotomies, with the
fewest complications.
Improvement of Radio Opacity of Injectable Bone Substitute MBCP GelTM for Minimal Invasive Surgery MIS
Authors: Daculsi G. , Aguado Eric , Corre Pierre , Bourges Xavier , Baroth Serge , Goyenvalle Eric
Published: March 2009

Dedicated to Minimal Invasive Surgery MIS particularly in spine for vertebroplasty, the
surgeons and radiologists ask for improvement of radio opacity, to be sure of the injection site, and to
prevent injection in blood vessels. MBCP Gel® is an Injectible biomaterial non self hardening, the
biomaterials consists of BCP granules associated with a hydrosoluble polymer. These materials have
been shown to be perfectly biocompatible and potentially resorbable and, thanks to their initial
plasticity, they assume the shape of the bone defects very easily, eliminating the need to shape the
material to adjust to the implantation site. MBCP gels do not have mechanical properties like the
hydraulic bone cements. However bone cells are able to invade the spaces created by the
disappearance of the polymer carrier. Bone ingrowth takes place all around the granules at the expense
of the resorption of the BCP granules. In time, the mechanical property is increased due to the
presence of the newly formed bone. This study demonstrates an improvement of MBCP gel by freeze
drying and reconstitution using iodine solution or sterile water in a classical model of rabbit bone
defects.
Pilot Study of Safety and Performance of a Mixture of Calcium Phosphate Granules Combined with Cellulosic-Derived Gel after Tunnel Filling Created during Surgical Treatment of Femoral Head Aseptic Osteonecrosis
Authors: Fabre Thierry , Chauveaux Dominique , Moinard Maryse , Mais Claude , Durand Marlene , Pollart Claire , Daculsi G.
Published: March 2009

The biomaterial studied here is a composite associating a mineral phase of an intimate
nanoscale melting of hydroxyapatite and beta tri calcium phosphate and an aqueous phase
containing a synthetic polymer derived from cellulose HPMC (hydroxyl propyl methyl cellulose),
marketed under name MBCP Gel (FDA approval, Biomatlante manufacturer). The present
exploratory study aim was to study the safety of MBCP-gel, and to determine in the osseous healthy
area the performance of MBCP gel. We expected to prove bone ingrowth into the osseous cavities
created during drilling biopsy of the aseptic osteonecrosis of femoral head. The current results
obtained in the first two patients with 1 year follow up demonstrate the resorption and bone
ingrowth with trabecular bone architecture in the hole created into the femoral neck.
Antibacterial Effects of Sol-Gel Derived Zinc-Containing Hydroxyapatite
Authors: Shi Xin Chang , Jiang H.Z. , Xue J. , Liao Yun Mao , Xiao L.Y. , Bao C.Y. , Li W.
Published: March 2009

In order to modify the biological properties of pure hydroxyapatite (HAp), two kinds of zinc-containing HAp, which had zinc content of 5.10wt% and 2.54wt%, respectively, were synthesized via sol-gel technique. The obtained coatings were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). Then the antibacterial effects were evaluated through bacteriostatic test on Streptococcus mutans (S.mutans) in vitro and zinc ions releasing ability was investigated through detecting the zinc ions concentration by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The obtained coatings were observed to possess typical apatite peaks in XRD patterns and high homogeneous and porous surfaces in SEM morphology. The coating layer demonstrated good releasing ability in Brain Heart Infusion (BHI) liquid and obviously inhibitory effects to the growth and proliferation of S. mutans. Based on the results obtained above, it is concluded that the sol-gel derived zinc-containing hydroxyapatite could be applied as an antibacterial effective biomaterial.
The Effect of Slip Loading on the Properties of Porous Calcium Phosphate Bioceramics
Authors: Hsu Y.H. , Turner I.G. , Miles A.W.
Published: March 2009

Ceramic slips with powder loadings in the range of 80-140 wt% were used to investigate
the effect of slip loading on the physical and mechanical properties of open pore HA/TCP
bioceramics. The results indicated that increasing the slip loading had an effect on the properties of
the samples. The average apparent density, the work of fracture and compressive strength all
increased with slip loading. In contrast, the effect of increasing slip loading on the four-point bending
strength was not significant.
Regulating Size, Morphology and Dispersion of Nano-Crystallites of Hydroxyapatite by pH Value and Temperature in Microemulsion System
Authors: Jiang F.X. , Lu X.Y. , Zhang M.L. , Weng Jie
Published: March 2009

Nanosized hydroxyapatite (nano-HA) in narrow size distribution was prepared in the
microemulsion system. The experimental factors of pH values and temperature were specially
investigated in order to receive nano-HA particles with the required morphologies. Several kinds of
nano-HA with different shapes, sizes and crystallization were obtained by regulating the above
factors in the experiment. After the as-received nano-HA particles were heat-treated at an elevated
temperature, they became a kind of globular particles with an average size of 60nm and showed
excellent disperse ability in absolute alcohol.
Combined Structural Investigations of Bioactive Silicate Glasses
Authors: Malz Frank , Aguiar H. , Solla Eugenio Luís , Serra Julia , González Pio , León Betty , Jaeger Christian
Published: March 2009

The results of a combined structural characterisation (XRD, IR, NMR, SEM, TEM) of a
phosphate containing Mg-Ca silicate and a phosphate containing Na-Ca silicate glass samples are
presented. The structural results are also compared with in vitro tests carried out in simulated body
fluids for checking bioactivity.