bluuebunny/crossref_metadata_2025 huggingface dataset:
Hot Deformation Behavior and Microstructure Evolution of Ti-6.5Al-1.5Zr-3.5Mo-0.3Si with an Equiaxed α+β Starting Structure
Authors: Chen Hui Qin , Lin Hao Zhuan , Guo L. , Cao Chun Xiao
Published: March 2009

The hot deformation behavior of TC11 with an equiaxed α+β pre-form microstructure
was investigated by hot compression tests in the temperature range 800°C–1090°C and strain rate
range 1×10-310s-1. Several approaches have been used in this investigation, which include
analysis of shapes of stress–strain curves, kinetic analysis and microstructure observation. The
experimented results showed that, (1) In the β phase field, the alloy exhibits dynamic
re-crystallization. The apparent activation energy in this domain is estimated to be 183kJ/ mol,
which is close to that for self-diffusion in β. The re-crystallized grain size may be governed by
competing of diffusion and dynamic re-crystallization rate at deforming conditions. (2) In the α+β
phase field, the alloy exhibits super-plastic deformation behavior at 0.001-0.01s-1 and 980°C
-850°C, and the apparent activation energy estimated in this domain is about 600 kJ/mol, which is
much higher than that for self-diffusion in α-titanium due to β volume fraction is not constant over
the test temperature range.
Microstructure of AZ91D in Different Treatment Conditions
Authors: Zhang Jin , Tao Yan Ling , Sun Zhi Fu
Published: March 2009

The microstructures of magnesium alloy AZ91D in as-cast, solid solution and aging
conditions were studied by optical, scanning electron and transmission electronic microscopes. The
relationship between microstructure and the microhardness was analyzed. It has been found that the
microhardness in the matrix varied slightly with the increasing solution time, but increased quickly
with the aging time. The difference of the microhardness between the matrix and the second phase in
as-cast condition is larger than that in T6 aging condition, because the aluminum-zinc-magnesium
(poor) phase existed in the as-cast condition.
First-Principles Study on Initial Oxidation of NiAl(110)
Authors: Hu Jun Min , Shang Jia Xiang , Zhang Yue , Zhou Chungen , Xu Hui Bin
Published: March 2009

The oxygen atom adsorption at Al-Al bridge, Ni-Ni bridge, Al top and Ni top site on the
NiAl(110) surface by first-principles method within density functional theory has been studied in this
paper. It has been found that the preferred adsorption position of the oxygen was at the Al-Al bridge
site then the Ni-Ni bridge site. The charge transfer took place obviously between the O atom and the
nearest Al atoms, but no charge transferred from the nearest Ni atoms to O atom. For the Al-Al
(Ni-Ni) bridge adsorption site, the bond lengths of Al-O and Ni-O were about 1.741 Å (1.700Å) and
2.369Å (2.012Å), respectively, which means that the Al atom is easier to be oxidized than the Ni
atom. It is revealed that the Al atom oxidized selectively and the chemical bond formed between the O
ion and the nearest Al ions during the initial oxidation stage.
Low-Cycle Fatigue Behavior of Three Die Cast Magnesium Alloys
Authors: Wang Chang Yi , Liu Zhen , Chen Li Jia
Published: March 2009

Totally strain-controlled low cycle fatigue tests with a strain ratio Rε= -1 were carried out
on die-cast AZ91HP, AM50HP and AE 42 alloys at a constant strain rate of 2.5×10-3 s-1 and room
temperature. The cyclic deformation behavior of the three alloys was investigated through the
characteristics of representative hysteresis loops at various total strain amplitudes. Cyclic deformation
hardening was observed and the low-cycle fatigue life data were analyzed using the well known
Basquin and Coffin-Manson equations. The transition life of the three alloys is considerably low,
which can be attributed to the low ductility of these die cast Mg alloys.
Room and Elevated Temperature Mechanical Properties of Hot-Pressed Uni-Cf/SiO2 Composite
Authors: Zhou G.H. , Wang Shi Wei , Huang Xiao Xian , Guo Jing Kun
Published: March 2009

Unidirectional carbon fiber reinforced fused silica (uni-Cf/SiO2) composite was prepared
by slurry infiltration and hot-pressing. The room and elevated temperatures flexural properties were
investigated and the fracture features of the composite were observed. This composite exhibited
non-catastrophic failure at room and elevated temperatures. The oxidation of carbon fiber at elevated
temperatures was the main reason for the degradation of flexural strength and elastic modulus. The
flexural strength tested at 1200 was 376MPa and exhibited anomalously higher than that at 1000
(277MPa), which was attributed to the viscous flow of fused silica matrix and therefore the
occurrence of microcracking in the matrix was deferred. And it was inferred that the brittle to plastic
transition temperature (Tb-p) of uni-Cf/SiO2 composite corresponded to a certain temperature around
1200°C.
Compression Deformation Behavior of AZ91D Magnesium Alloy in Semi-Solid State
Authors: Yang Ming Bo , Pan Fu Sheng , Tang Li Wen , Hu Hong Jun
Published: March 2009

The semi-solid compression deformation behavior of the AZ91D alloy with non-dendritic
structure, which was obtained under the semi-solid isothermal treatment condition of 570°C×60min,
was studied by means of Gleeble-1500 thermal-mechanical simulator. When the compression strain
was lower than 0.7, along with the compression strain increasing, the compression stress firstly
increased rapidly, then decreased rapidly, and finally kept a constant stress level gradually. Under the
condition of different deformation temperatures and deformation rates, the maximum compression
stress was obtained simultaneously when the compression strain value was 0.025 approximatively.
Furthermore, when the deformation rate kept a constant, the compression stress decreased along with
the deformation temperature increasing, and when the deformation temperature kept a constant, the
compression stress increased along with the deformation rate increasing.
Studies on Thermal Property of Silica Aerogel/Epoxy Composite
Authors: Zhao Jiu Peng , Ge Deng Teng , Zhang Sai Lei , Wei Xi Long
Published: March 2009

Silica aerogel/epoxy composite, a kind of efficient thermal insulation material, was
prepared by doping silica aerogel of different sizes into epoxy resin through thermocuring process.
The results of thermal experiments showed that silica aerogel/epoxy composite had a lower thermal
conductivity (0.105W/(m·k) at 60 wt% silica aerogel) and higher serviceability temperature
(Martens heat distortion temperature: 160°C at 20 wt% silica aerogel). In addition, the composite
doping larger size (0.2-2mm) of silica aerogel particle had lower thermal conductivity and higher
Martens heat distortion temperature. Based on the results of SEM and FT-IR, the thermal transfer
model was established. Thermal transfer mechanism and the reasons of higher Martens heat
distortion temperature have been discussed respectively.
Acoustic Emission Research on Thermal Shock Behaviors of Three-Dimensional C/SiC Composites in Different Environments
Authors: Fang Peng , Cheng Lai Fei , Zhang Li Tong , Mei Hui , Zhang Jun
Published: March 2009

Three-dimensional (3D) carbon fiber reinforced silicon carbide matrix composites (C/SiC)
were prepared by a low-pressure chemical vapor infiltration method. The thermal shock behaviors of
the composites in different environments were researched using an advanced acoustic emission (AE)
system. Damage initiation and propagation were easily detected and evaluated by AE. The thermal
shock damage to C/SiC composites mainly occurred at the process of cooling and was limited at argon
but unlimited at wet oxygen atmosphere. Also correlations have been established between the
different damage mechanisms and the characteristics of acoustic emission signals obtained during
thermal shock tests. In this way, the paper contributes to the development of the acoustic emission
technique for monitoring of damage development in ceramic-matrix composites.
Influence of NiCoCrAlY and Diffusion Aluminide Coating on Oxidation and Hot Corrosion of a Ni-Based Superalloy
Authors: Xie Dong Bai , Zhu Sheng Long , Dai Wen Jun , Wang Fu Hui
Published: March 2009

The most common metallic coatings used in today’s gas turbine engines are MCrAlX
(where M is Ni and/or Co and X is one or more reactive elements such as Y, Hf, etc.) type overlay
coatings. However, overlay coating techniques (plasma and flame spraying or physical vapor
deposition) are line-of-site processes, and so, it is possible not to deposit coating on some surface of
the complex turbine components. The diffusion aluminide coatings can solve this problem. A
NiCoCrAlY and diffusion aluminide coating were prepared on K38G cast alloy by multi-arc ion
plating and low pressure chemical vapor deposition (LP-CVD) techniques, respectively. The
isothermal oxidation behavior of K38G and the coatings was studied in air at 900 and 1000 oC. Their
hot corrosion behaviors in the presence of 75 wt.% Na2SO4+K2SO4 and 75wt.%Na2SO4+NaCl film at
900oC were studied. The results showed that the two kinds coatings exhibited low oxidation rate at
900 and 1000oC and the presence of salt accelerated the oxidation rate. The NiCoCrAlY coating
showed the better hot corrosion resistance than the aluminide coating.
Evaluation of Tribological Properties of a Cathodic Arc Ion-Plated CrSiN Coating under Both Unlubricated and Boundary-Lubricated Conditions
Authors: Ouyang Jia Hu , Murakami Takashi , Sasaki Shinya , Zhou Yu
Published: March 2009

The friction and wear characteristics of a cathodic arc ion-plated CrSiN coating in sliding
against different counter materials have been investigated under both unlubricated and
boundary-lubricated conditions. Under boundary-lubricated conditions, the CrSiN coating exhibits a
friction coefficient of 0.12 to 0.20 against a SAE 52100 steel ball and of 0.04 to 0.07 against a
CrN-coated steel pin, depending on wear parameters used. The effects of load, temperature and
counter materials on friction and wear of the CrSiN coating were discussed. The worn surfaces and
wear debris generated under different wear conditions were examined by means of scanning electron
microscopy and Raman spectroscopy to identify the tribochemical reaction and phase structures
generated during the wear process. Under unlubricated conditions, iron-based oxides formed in
sliding against a steel ball, while some chromium oxides were identified on worn surfaces of the
CrSiN coating in sliding against an alumina ball in air.
Microarc Oxidation Coatings Fabricated on Ti3Al-Based Alloy in Silicate Electrolyte
Authors: Li Xi Jin , Xue Wen Bin , Wu Xiao Ling , Cheng Guo An , Zheng Rui Ting
Published: March 2009

The ceramic coatings with thickness up to 120 μm were prepared on Ti3Al-based alloy in
silicate electrolyte by microarc oxidation method. The morphology, microstructure, composition and
phase constituent of the coatings were investigated. Microhardness profiles along the cross-section of
the coating were determined. The maximum microhardness in the coating was about 3 times higher
than that of the substrate. The thickness of the coating increased with the increasing of MAO time.
There were two layers in the ceramic coatings: a dense layer and a loose layer. The coating was mainly
composed of (Ti0.6Al0.2Nb0.2)O2 phase. Scratching test revealed a good adhesion between the Ti3Al
substrate and the coating.
Preparation of High Silicon Steel by EB-PVD
Authors: Li Xiao , He Xiao Dong , Li Yao , Sun Yue
Published: March 2009

In the process of preparation of high silicon steel by EB-PVD, the effect of distance
between ingot and substrate on the weight percent of silicon in the silicon steel was investigated
through specially designed experiment. Energy dispersive spectroscopy (EDS), optical microscope
(OM), scanning electron microscopy (SEM), x-ray diffraction (XRD) were used to characterize the
weight percent of silicon, microstructure, crystal grain size and phase of the high silicon steel. The
experimental results show that the weight percent of silicon in the silicon steel decreases with
increasing of the distance between ingot and substrate, when the distance is about 415 mm, high
silicon steel can be fabricated by EB-PVD. The microstructure of the high silicon steel was composed
of columnar crystal grain, the size of the crystal is about 25-50 μm. The material back to the substrate
side is composed of B2 and exhibits strong {400} texture.
Effect of Temperature on La1.85Sr0.15CuO4 Single Crystal Growth by Floating Zone Method
Authors: Xiang X.Q. , Qu J.F. , Zhang Y.Q. , Lu X.L. , Li X.G.
Published: March 2009

Superconducting single crystals of La1.85Sr0.15CuO4 have been grown at various
temperatures without single crystal seeds by the traveling-solvent floating-zone method. In order to
avoid the formation of bubbles during the crystal growth process, a flowing atmosphere of 2 atm
oxygen or 1 atm air was applied in different temperature range. It was found that the crystal quality
could be improved by raising the growth temperature in a certain range, and the orientation changed
from (110) to (100) at higher temperature. X-ray diffraction results showed that the full-width at
half-maximum of the best as-prepared crystal was 0.086°. The crystals grown in 2 atm oxygen
showed a superconducting transition temperature (Tc) of 37.3 K, while the crystals grown in floating
air showed a Tc of about 35 K and it could be improved to 36.5 K by annealing in flowing oxygen.
Critical and Irreversibility Temperature Study of Internal-Sn Nb3Sn Superconducting Wires
Authors: Zhang C.W. , Sulpice Andre , Soubeyroux Jean Louis , Tournier Robert F. , Zhou Lian , Tang X.D. , Verwaerde Christophe , Hoang G.K.
Published: March 2009

In order to optimize the synthesis process of internal-Sn Nb3Sn wires, magnetization
measurements have been performed on samples reacted at various temperatures between 650 and 725
°C and for time ranging from 8 to 200 h We compared samples of various origins, from NIN in Xi'an
and Alstom in Belfort. These measurements give us access to critical and irreversibility temperatures.
Although all Nb-Sn phases are superconductive, their critical temperatures are varying from 6 K
(18at%Sn) to 18.3 K (25%atSn : stoichiometric Nb3Sn). Thus, Tc and T* measurements are related to
the progress of tin diffusion and reaction in the wires. We correlate the results of magnetization with
SEM (Scanning Electron Microscopy) and EDS (Energy Dispersive Spectroscopy) observations,
which indicate directly the Sn content distribution across Nb filaments.
Influences of Preparation Conditions on Melting and Reformation Behaviors of (Bi,Pb)-2223 Core in the Ag-Sheathed Tape
Authors: Li J.Y. , Zheng H.L. , Li J.G. , Li Cheng Shan , Lu Ya Feng , Zhou Lian
Published: March 2009

Three kinds of Ag-sheathed (Bi,Pb)2Sr2Ca2Cu3O10 ((Bi,Pb)-2223) monofilamentary tapes
were fabricated by powder-in-tube (PIT) process under different conditions. The phase evolutions
during melting and reformation of (Bi,Pb)-2223 core in them have been investigated by ex-situ X-ray
diffraction (XRD) analysis. The short tapes were melted at 855°C, 858°C in 7.5% O2 balanced with
argon, and then slowly cooled to 801°C and 804°C at 1.5°C/h, respectively. The results show that the
(Bi,Pb)-2223 phase can reform directly from the melt in all three tapes if the appropriate melting
temperatures are used. However, the ceramic cores underneath the silver sheath exhibit different
melting and recrystalization behaviors, as the differences of phase compositions in the original tapes
before melted.
Preparation of YBCO Superconducting Films by Sol-Gel Process
Authors: Zhao Gao Yang , Zhang Huang Li , Xue Ren Zhong , Chen Yuan Qing , Lei Li
Published: March 2009

precursor solution was prepared using barium trifluoroacetae (Ba-TFA) and non-fluorine
yttrium (Y) and copper (Cu) organic salts. The precursor solution was modified by benzalacetone
(BzAcH), in which the Cu2+ were chelated with BzAcH, which preventing the loss of Cu in the
pyrolysis process. Dense YBCO superconducting films with smooth surface, which confirmed by
scanning electron microscopy (SEM), were repeatedly obtained through sol-gel process. X-ray
diffraction (XRD) 2θ scanning and φ scanning indicated that the as-prepared YBCO films had good
c-axis texture. YBCO films with superconducting transition temperature (TC) above 89K were
obtained.
Epitaxial Growth of CeO2 Buffer Layers on Both YSZ Single Crystal and Textured Ni5W Substrates by MOD Method
Authors: Zhang Ying Xiao , Suo Hongli , Zhao Yue , Liu Min , Wang Rong , He Dong , Ma Lin , Zhou Mei Ling
Published: March 2009

CeO2 has been considered as one of the most lattice compatible and chemically stable
materials for YBa2Cu3O7-x coated conductors. In this paper, we presented the epitaxial growth of
CeO2 thin film on both YSZ single crystal and cube textured Ni5W substrates by MOD method.
Homogenous, crack-free and dense CeO2 thin films on both substrates with sharp biaxially cube
texture were fabricated by post-annealing the precursor films at 1000-1150°C. For the CeO2 film on
the textured Ni5W substrate, the FWHM values of (111) Phi-scan and (002) rocking curve were
around 6°and 7°, respectively, the surface roughness was less than 2 nm over an area of 1μm×1μm
observed by AFM. It was found that the CeO2 thin film improved both the in-plane orientation and
surface roughness of the Ni5W substrate, indicating that the as deposited CeO2 films were suitable
for the further growth of YBCO superconductor layer.
Investigation Texture in Ni-W Alloy Substrates for Coated Conductors
Authors: Zhao Yue , Suo Hongli , Liu Min , He Dong , Zhang Ying Xiao , Ma Lin , Zhou Mei Ling
Published: March 2009

It is well know that Ni-5at.% W(Ni5W) and Ni-9.3at.% W(Ni9W) alloy substrates are
two kinds of promising materials to be employed in coated conductors. The Ni5W substrate is very
easy to produce cube texture, while the Ni9W alloy has a lower magnetic property and higher
strength. However, the pure cube texture are not capable to be obtained in Ni9W alloy. In this work,
the preparation and texture development in both Ni5W and Ni9W alloy substrates have been
reported. Highly biaxial textured Ni5W substrate was fabricated by cold rolling, followed by three
different annealing routes. The texture analysis indicated that a sharp cube texture was formed after
annealing at a wide temperature range of 800-1100°C in as rolled Ni5W substrate. The high quality
of cube orientation was obtained after a two step annealing (TSA) with farthing twin boundaries
analyzed by EBSD. Furthermore, in order to obtain a pure cube texture in Ni9W alloy substrate, a
typical rolling process was performed and the deformation texture was optimized in these
substrates. The designed deformation texture components were obtained in Ni9W alloy when
pre-heating the ingot at 250 °C before performing a cold rolling, which shows a possibility to form
cube texture in Ni9W alloy substrate after annealing.
Microstructure and Precipitates in Mg-Zn-Y Alloys
Authors: Zhang M. , Zhang Wen Zheng , Yuan Guang Yin , Zhao Q.L.
Published: March 2009

The present work studied the precipitate microstructures in as-cast Mg-Zn-Y-Zr alloys. The
experimental result showed that there is significant number of small precipitates within the grains
besides the icosahedral quasicrystals along the grain boundaries. Among these precipitates, a new
phase has been identified. The new phase displays square morphologies with the size in the range of
200 nm to 2 μm. According to the energy dispersive spectrometer (EDS), this phase could be a
metallic Y-riched compound. The diffraction patterns can be indexed with an f.c.c. structure with the
lattice parameter a = 0.52±0.1 nm. The structure does not agree with any precipitate structures that
have been reported from the previous studies of Mg-Zn-Y alloys.
Levitation Capability of a Bulk YBa2Cu3O7-x with NdFeB Guideway by Two Magnetization Methods
Authors: Zheng Jun , Li Jing , Deng Zi Gang , Song Hong Hai , Wang Su Yu , Wang Jia Su
Published: March 2009

On the requirement of high temperature superconducting (HTS) Maglev transportation
application, levitation capability of bulk YBa2Cu3O7-x on the HTS Maglev test vehicle has been
investigated experimentally by pulsed field magnetization (PFM) and field cooling (FC). The result
showed that YBa2Cu3O7-x sample magnetized by the pulsed magnetic field behaves like a magnet in
the other external field, and the magnetization direction of bulk determines its levitation force and
lateral force mode (magnitude and direction) over NdFeB permanent magnetic guideway (PMG). On
the other hand, static field cooling condition is with an electromagnetic field realized by Field Control
Electromagnets Workbench. Two important forces of the same bulk were measured and compared
with the PMG when the bulk had the same max trapped field by FC and PFM methods, and the results
show the difference effects by these two magnetization methods.
Influence of RE on Microstructure and Mechanical Properties of Mg-Li-Al Alloys
Authors: Liu Bin , Zhang M.L. , Niu Zhong Yi
Published: March 2009

A series of alloys were designed and prepared using vacuum melting furnace. The as-cast
microstructure and phase compositions of these alloys were characterized by optical microscope,
X-ray diffraction (XRD) and scanning electronic microscope (SEM). The hardness and mechanical
properties of alloys at room temperature were measured as well. The results show that the addition of
RE leads to the formation of intermetallic Al3La distributed within grain boundaries. The
intermetallic compound with oriented structure impedes grain growth, and refines the grain. The
strength and the hardness of the alloys increase with the increase of the RE content in the range of
0.2-0.8 wt %.
Simultaneous Substitution of Y and Ba by Ca in YBCO
Authors: Zhang L. , Yu Jing , Zhang Han
Published: March 2009

A series of samples of Y1-xCaxBa2Cu3Oy (YCBCO) were synthesized with 0.05≤x≤0.3
and characterized by DC magnetization, X-ray diffraction (XRD), and Rietveld refinement. It was
found that Ca replaces Y and Ba in YBa2Cu3Oy (YBCO) simultaneously, and the amount of Ca in the
Y and Ba positions is estimated by the refinement，respectively. The experimental results showed
that the structural changes had a close correlation with Tc. With careful analysis of the change of the Tc
below and above x=0.2 and the changes of the bond lengths, such as Cu(2)-O(2) and Cu(2)-O(3), it is
suggested that the Ca substitution for Y suppresses the Tc more strongly than that for Ba.
Magnetic and Transport Properties of Mn-Si Films Synthesized on 4H-SiC(0001) Substrates
Authors: Wang Wen Hong , Takano Fumi Yoshi , Ofuchi Hiro Nori , Akinaga Hiro
Published: March 2009

We report a systematic study of the thickness dependence of magnetic properties in
carbon-incorporated Mn-Si films synthesized on a 4H-SiC(0001) homoepitaxial wafer by molecular
beam epitaxy (MBE) and an annealing method. Magnetization characteristics reveal a dual-phase
characteristic in films with decreasing thickness. The anomalous Hall effect has been observed in the
thicker film; however, the observed temperature dependence cannot be explained by traditional
anomalous Hall effect theory. The temperature dependent resisitivity indicates the film has a metallic
behavior.
Electrochemical Fabrication of BixTe1-x (0.4 ≤ x ≤ 0.7) Nanowire Arrays
Authors: Wang Wei , Qu J.F. , Lu X.L. , Zhang G.Q. , Li Guang , Li X.G.
Published: March 2009

Large scale and highly ordered thermoelectric BixTe1-x (0.4 ≤ x ≤ 0.7) nanowire arrays
were successfully fabricated by cathodic electrolysis into porous anodic alumina membrane (AAM)
templates in aqueous solution. The structure of the nanowires was characterized by X-ray
diffraction and selected-area electron diffraction (SAED). Field emission scanning electron
microscopy (FE-SEM) and transmission electron microscopy (TEM) results show that the
nanowires are smooth and uniform with the diameters of about 50 nm and lengths up to tens of
micrometers. Energy dispersive spectroscopy (EDS) was used to check the exact stoichiometry of
as-prepared samples. The results reveal that the atomic ratio between Bi and Te can be modulated
effectively by controlling the concentration of the electrolyte solution. The synthesis of high quality
BixTe1-x nanowires with controllable x is significant for optimizing the thermoelectric performance.
Giant Magnetostrictive Material Actuator Based Active Vibration Control-a Modified α - LMS Algorithm
Authors: Song Zhao Qing , Zhou Shao Lei , Shi Xian Jun , Liang Guo Qiang
Published: March 2009

A modified α-LMS algorithm is presented and is applied to the controller design of active
vibration control. A magnetostrictive material actuator is used as experimental equipment for active
vibration control in this paper. The merit of the presented method is that it is not necessary to build the
mathematical model of magnetostrictive actuator. The experimental result shows that the controller
designed is efficient for active vibration control.
Modeling Rate-Dependent Hysteresis for Magnetostrictive Actuator
Authors: Zhen Zhang , Mao Jian Qin
Published: March 2009

The rate-dependent hysteresis exhibited by magnetostrictive actuator (MA) presents a
challenge in modeling of these actuators. In this paper, a novel rate-dependent hysteresis model was
proposed for magnetostrictive actuator. In the model, the modified Prandtl-Ishlinskii operator (PI) is
combined with a second order ordinary differential equation in a cascaded structure. The modified PI
operator is used to account for the static hysteresis, the connection between ODE and the
rate-dependent energy loss was established, including the classical eddy current loss and the
mechanical dynamics. Simulation results show a good agreement with the experiment ones.
Numerical Simulation of Magnesium Alloy AZ31B Sheets with Thermal Deep-Drawing Process
Authors: Yu Yan Dong , Li Cai Xia
Published: March 2009

The finite element numerical simulation for the formability of magnesium alloy AZ31B
sheets with thickness of 0.8mm and diameter of 140mm has been proceeded to investigate the
formability using the current finite element software. Under the condition with blank holder force of
8KN and deep drawing speed of 0.3mm/s at 200, the sytematic analysis and prediction of the
thickness change and the forming rule for thesimulation process of the blank has been carried out.
Under the same parameter, the drawing parts by deep drawing with a hydaulic machine were obtained
and the thickness tested. It has been found that thickness change rules and the forming rules of the
experimental results were in agreement with the numerical simulations.
Effect of Nd on Microstructures and Properties of AZ31 Wrought Mg Alloy
Authors: Qiu Wei , Han En-Hou , Liu Lu
Published: March 2009

Addition of RE elements to Al-containing Mg alloys can improve properties of Mg alloys
at elevated temperatures. In the present investigation, hot-extruded AZ31+x%Nd.
(x=0.1,0.3,0.6and1.0 wt%) wrought Mg alloy were prepared .The effects of Nd on microstructures
and mechanical properties at room temperature of new alloy were investigated. The investigation
found that Nd can bring about two kind of precipitation phases . One is AlNd phase, the other is
AlNdMn phase, which were identified as Al11Nd3 and Al8NdMn4 by X-ray diffraction and TEM.
Influence of Rolling Temperature on Microstructure and Tensile Properties of AZ31 Sheets
Authors: Li Da Quan , Wang Qu Dong , Ding Wen Jiang
Published: March 2009

Microstructure and tensile properties of AZ31 rolled at different temperatures were
characterized. Rolling of extruded AZ31 plates was carried out at room temperature, 573K, 623K and
673K. Cold rolling of extruded AZ31 plates was difficult due to the poor formability at room
temperature. And deformation twinning plays an important role in rolling of AZ31 alloy at room
temperature. The microstructural analysis showed that the nucleation of dynamic recrystallization
(DRX) occurred at 573K, DRX was almost completed at 623K and grain growth was determined at
673K. The ultimate tensile strength (UTS) as large as 377MPa was achieved after rolled at 573K. And
the anisotropy in strength was obviously examined due to the rolling texture. The anisotropy reduced
as rolling temperature increasing from 573K to 673K and this may be attributed to the completion of
DRX.
Effect of Cooling Rate on the Microstructure and Mechanical Properties of ZK60 Alloy
Authors: Lin Jin Bao , Wang Qu Dong , Peng Li Ming , Zhou Yang , Ding Wen Jiang
Published: March 2009

Microstructure and mechanical properties of Mg-6.0wt%Zn-0.5wt%Zr (ZK60) alloy were
studied as a function of cooling rate. The temperature field and cooling rate during the casting process
were investigated by use of finite element analysis (FEA) simulation. The results showed that the
microstructure was refined and the eutectic phase distributed much uniformly with the increase of
cooling rate. The increase of yield strength, ultimate strength and elongation can be ascribed to the
strengthening effect of fine grain. Relationship between grain size and yield strength is consistent
with the Hall-Petch formalism: 1/ 2 80.37 132.56 − = + d y σ .
Warm Hydroforming of Magnesium Alloy AZ31 Sheets
Authors: Zhang Shi Hong , Ren Li Mei , Zhou Li Xin , Xu Yong Chao , Palumbo G. , Ricarico L.T.
Published: March 2009

In the present study, warm hydroforming of cell phone cases with magnesium alloy AZ31
sheets was investigated. Fine-grained magnesium alloy sheets were prepared by cross rolling. And
the tensile tests were first conducted in order to determine the proper forming temperature. The
results showed that the most suitable temperature range appears to be 150-200°C. At last, the
magnesium alloy cell phone cases characterized with the small round radius of all edges were formed
successfully at 170°C with the low punch velocity and the maximum pressure not less than 5MPa.
Annealing Process Optimization of a ME Wrought Magnesium Alloy
Authors: Zhao Ya Zhong , Pan Fu Sheng , Peng Jian , Zhou Jun
Published: March 2009

The properties and microstructures after different annealing processes of an as-extruded
ME magnesium alloy were investigated. The results showed the better properties with the tensile
strength of 205 MPa and the elongation of 19.8%, respectively, could be obtained after annealing at
623 K for 4h and air-cooled, meaning that elongation value increased 40% than that of as-extruded
sheets while the strength remained almost same. The annealing hold time corresponding with the
higher elongation would shorten with the increase of annealing temperature. There is legible necking
on broken tensile specimen. The behavior of fracture showed obvious characteristic of ductile
rupture, with many tearing edges and cavities.
Effect of Rolling and Annealing on the Mechanical Properties and Microstructure of AZ31 Magnesium Alloy
Authors: Huang Guang Jie , Wang Ling Yun , Huang Guang Sheng , Pan Fu Sheng , Liu Qing
Published: March 2009

Microstructural evolution and mechanical properties of the AZ31 magnesium alloy during
rolling and annealing process were investigated. The sheet samples were prepared after different
stages of the hot rolling, cold rolling and annealing processes. The hot rolling temperature was
between 300-450C and the final thickness of the cold rolled sheets was 1.5mm. The cold rolled
sheets were annealed at different annealing temperature (260-350C) for different time (10~120min).
Tensile test was performed to investigate the mechanical properties of the samples obtained from
different stages. With aid of the optical microscopy, scanning electron microscopy (SEM) techniques,
the microstructure of the samples were characterized and the results were related to the mechanical
properties. It was found the hot-rolled sheets exhibit higher ductility comparing with the cold-rolled
sheets. The microstructural investigation showed that the microstructure of the hot-rolled samples
was dominated by recrystallized equiaxed grains while the microstructure of the cold-rolled samples
dominated by deformation twining. By applying annealing on the cold-rolled sheets, fine
recrystallization grains were obtained and ductility of the samples was improved. The effects of the
grain size and twining on mechanical properties of the AZ31 sheet were further discussed based on
the experimental results.
Effect of Hot Extrusion, Hard Drawing and Heat Treatment on Properties and Structure of MB5B Wrought Mg Alloy
Authors: Li Xing Gang , Zhang Kui , Li Yong Jun , Mi Xu Jun , Xiong Bai Qing , Hu Chun Li
Published: March 2009

The experiments of hot extrusion, hard drawing and annealing treatment were carried out in
this paper in order to study the effects of these processes to the mechanical properties and structure of
MB5B wrought magnesium alloy. The experimental results showed that, the eutectic phase was to
melt into magnesium matrix greatly during the heating process and precipitated from matrix with
point-like state in transverse section after extrusion. The tensile strength and elongation of billets after
above mentioned treatment were equal to those after homogenization treatment. The as-received
billets are then drawn continuously under the circumstance that the percent reduction in area(ψ) of
each pass was no more than 15% and the total reduction in area was no more than 50%. As the results
the tensile strength increased and elongation decreased sharply at the same time. The grains and
eutectic phase of alloy after drawing were prolonged significantly. The subsequent heat treatment had
little effects on the properties of the hard drawn bar.
Study on the Process and Mechanism of Rolling-Bonding between Magnesium and Aluminum
Authors: Wang Qun Jiao , Le Qi Chi , Zou W.W. , Chen Jin Geng , Cui Jian Zhong
Published: March 2009

Application of magnesium alloy is restricted by its bad formability and low corrosion
resistance. In order to resolve these problems, rolling-bonding has been tried as a new method.
Pre-heating, rolling and annealing were used in the process of bonding, and aluminum cladding
magnesium alloys obtained. The effects of many parameters in the processes of pre-heating, rolling
and heat-treatment on bonding strength have been analyzed, and the mechanism of rolling-bonding
been studied. It was found that intermediate phase played an important role in the bonding. Good
bonding of aluminum cladding magnesium alloys achieved after annealing at 200oC for 1 hour.
Overview of CAST and Australian Magnesium Research
Authors: StJohn David H.
Published: March 2009

The CAST Cooperative Research Centre was established in 1993 as a joint venture
between industry, research and government partners to carry out research and development in the area
of light metals. Over the thirteen years since its formation CAST has developed a world class research
program and, in addition to the significant application of outcomes by our industry partners, much of
our research is being commercialised. In addition, CAST has developed a significant education and
training program, a best practice technology transfer program for small and medium enterprises,
consulting and design activities and established an alliance with Advanced Magnesium Technologies
as a provider of their research and development needs. The development of CAST has been achieved
by cooperation between all our partners who represent most of the light metals research groups and a
significant proportion of light metals industries in Australia. The close involvement of the industry
partners in all aspects of the operation of CAST has ensured we have a program of activities focused
on delivering benefits to Australia’s light metals industry. This paper presents an overview of the
magnesium research undertaken by CAST and other research groups such as the Centre of Excellence
in Design of Light Metals and the CSIRO including their Light Metals Flagship program. Some
highlights are new magnesium powertrain alloys, an alloy suitable for decorative and domestic
applications called AM-lite, and new CSIRO casting technologies T-Mag and a twin roll strip casting
process.
Measurement of Press Creep Stress Exponent of ZM6 Alloy at Room Temperature
Authors: Zhong Ying Ying , Xu Shu Fang , Zhang Xin Ming , Guo Tian Cai , Deng Yun Lai
Published: March 2009

Nano-indentation technique was used to survey creep stress exponent of ZM6
(Mg-2.8Nd-0.7Zn-0.6Zr) alloy at room temperature. The results showed that average press creep
stress exponent of ZM6 alloy was about 89.75, and independent of strain rate and hardness, which has
been verified by linear relationship of the double logarithmic plots between strain rate ( ε& ) and
hardness (H ) measured by a nano-indentation equipment with constant load of 500mN.
Effects of Post Heat Treatment on the Interfacial Characteristics of Aluminum Coated AZ91D Magnesium Alloy
Authors: Zhang Jin , Wang Ying , Zeng Rong Chang , Huang Wei Jiu
Published: March 2009

Aluminum spray coating was applied onto AZ91D magnesium alloy. The effects of post
heat treatment on the interfacial characteristics, especially the diffusion kinetics of magnesium and
aluminum atoms across the interface were studied in this paper. It was observed that there was an
obvious interface between the aluminum coating and the magnesium alloy substrate. It was found that
post heat treatment could reduce the number of pores existed in the aluminum coating. The post heat
treatment resulted in not only the change in the composition and microstructure of the aluminum
coating, but also the improved metallurgical bonding between the coating and the substrate.
Effect of Aging on Electrochemical Behavior of T6-Treated WE54 Mg Alloy
Authors: Li Zhuo Qun , Shan Da Yong , Ke Wei , Han En-Hou
Published: March 2009

Microstructural examinations of T6-treated WE54 magnesium alloy were conducted after
different aging conditions, and the influence of aging on electrochemical behavior of this alloy was
investigated. For three batches of samples, with increasing aging time, the amount of precipitate
phases was greatly promoted, and they formed in a strengthening continuous way. Electrochemical
study showed that the value of corrosion potential followed the tendency to decrease when the aging
condition transformed from under-aged to peak-aged. However, after peak-aging, the corrosion
potential was raised to higher values. Explanations for the observed phenomena were based on the
relationship between microstructure, especially precipitate phases, and electrochemical behavior. At
under-aged condition, matrix served as galvanic cathode and precipitates acted as galvanic anode.
Because the amount of precipitate would rise with prolonging aging time, it is natural that corrosion
potential decreased. For over-aged alloys, metastable precipitate phases might in situ change to
equilibrium phases, rendering increase of corrosion potential possible.
Development of Magnesium Alloys with High Performance
Authors: Kamado Shigeharu , Kojima Yo
Published: March 2009

In Mg-Al-Zn and Mg-Al-Mn alloys containing 2.0~6.0mass%Al and 0~1.5mass%Zn,
grain refinement in the as-rolled (F) specimens containing large amount of Al and Zn are achieved by
both dynamic recrystallization and dynamic precipitation during hot rolling and leads to high strength
and high ductility at room temperature. At high temperatures, the tensile strength of the investigated
alloys is almost the same, while the elongation of the F-specimens increases with increasing Al and
Zn contents, leading to 150% in Mg-4.5%Al-1.5%Zn alloy. High Al and Zn contents alloys
significantly accumulate large working strain in grain interiors, and involve large amounts of high
angle grain boundaries and fine spherical precipitates, which can become the nucleation sites for
recrystallization. Therefore, dynamic recrystallization in such alloys occurs at small strain region
during tensile test. This dynamic recrystallization causes reduction of flow stress and large elongation
by grain boundary sliding at high temperatures. Furthermore, .fine recrystallized grains contributes to
deformation in normal direction, resulting in isotropic deformation behavior. Authors attempt to
improve proof stress and its anisotropic property of Mg-Al-Zn wrought alloys by grain size and
precipitates controls utilizing dynamic recrystallization and dynamic precipitation during hot
extrusion. In the alloy specimens extruded at lower temperatures increasing Al and Zn contents
enhance dynamic recrystallization and dynamic precipitation, resulting in grain refinement and large
amount of Mg17Al12 precipitates. As a result, the extruded Mg-9%Al-1%Zn alloy specimen shows
high tensile strength of 370MPa, 0.2% tensile proof stress of 240MPa and moderate elongation of
20%, which are almost same as standard values of tensile properties of T5-treated 6N01 Al extruded
alloy. Furthermore, a ratio of compressive proof stress to tensile proof stress of the as-extruded
specimen improves up to a higher ratio of 0.9 than that of Mg-3%Al-1%Zn alloy specimen with no
precipitation, 0.5, due to prevention of tensile twin, which easily occurs during compressive
deformation even under a low applied stress perpendicular to the extrusion direction, by dynamic
precipitation of Mg17Al12 phase.
Effect of Strontium on Mechanical Properties and Corrosion Resistance of AZ91D
Authors: Fan Yu , Wu Guo Hua , Zhai Chun Quan
Published: March 2009

With adding 2% strontium in AZ91D, the ultimate tensile strength and the elongation
increased by 10.3% and 55.3%, respectively. This is mainly caused by the refinement of the β phase
and the formation of Al4Sr strengthening phase. Furthermore, with adding 2% strontium in AZ91D
alloy, the weight loss corrosion rate in 5wt.% NaCl solution decreases to 0.048 mg·cm-2·d-1, which
was 33.8 % of the AZ91D corrosion rate. Therefore, the mechanical properties and corrosion
resistance of AZ91D could be improved by the addition of 2% strontium, which is due to the
refinement of Mg17Al12 phase and the formation of Al4Sr phase.
Characteristics of Acoustic Emission during Fatigue of As-Rolled AZ31B Magnesium Alloy
Authors: Zhou Hua Mao , Wang Jian Qiu , Zang Qi Shan , Han En-Hou , Ke Wei
Published: March 2009

The acoustic emission (AE) detected during the fatigue process in an as-rolled magnesium
alloy AZ31B was analyzed. Measurements were made during fatigue in air as well as in aqueous 0.1%
NaCl solution. Three stages of fatigue were detected with AE. It is concluded that plasticity, crack
extension or friction was the main AE sources during fatigue.
Modification of A3003 Alloy for Development of High Toughness Al Alloy Tube
Authors: Cho Hoon , Lee Byoung Soo , Jo Hyung Ho
Published: March 2009

The strength of aluminum alloys was improved by a severe deformation process while the
decrease of elongation leads to the defect. Modification of A3003 alloy was attempted in order to
develop a high strength and high formability Al alloy tube for the application of air-conditioning
systems in transportation, such as passenger planes and automobiles. An A3003 alloy was modified
by Ti addition, grain refiner. As a result of modification, the modified A3003 alloy was able to
suitably satisfy the mechanical strength requirements, including elongation. Grain size and secondary
dendrite arm spacing of A3003 alloy decreased by as much as 50 % by Ti addition. The finer grains
were uniformly distributed in the modified A3003 alloy billet. The yield strength of the modified
A3003 alloy was improved by 30 % without decreasing elongation.
Study on the Erbium Strengthened Aluminum Alloy
Authors: Nie Zuo-Ren , Li B.L. , Wang W. , Jin T.N. , Huang H. , Li H.M. , Zou Jing Xia , Zuo Tie Yong
Published: March 2009

We have systemically studied the effect of the erbium on the microstructure and the
mechanical properties in the 5xxx series aluminum alloys by using optical microscope, transmission
electron microscope (TEM) and by tensile testing. The results demonstrate that the tensile strength
increased quickly at the beginning of small contents of 0.1%Er both in the hot and cold rolled states,
then slowly increased with increasing the contents of Er until 0.4%, at which the best balance of the
strength and ductility (438MPa and 9.6%) were obtained. Microstructure observation in the hot rolled
state was indicated that the grain structure in the Er free Al-5Mg alloy revealed fully recrystallized
grain structure, while in the Al-5Mg containing Er was demonstrated deformation structure,
indicating the Er addition delayed the recrystallization behavior by the formation of the precipitation
of the Al3Er, which confirmed by means of the X-ray diffraction analysis. Furthermore in the TEM
microstructure observation the precipitation of Al3Er was distributed both in the grain interior and
subgrain or grain boundaries, which could be pinning the subgrain or grain boundary migration and
dislocation movement as well. Consequently the beginning of the recrystallization temperature in the
Al-5Mg containing Er was elevated about 50°C than in Al-5Mg without Er. This could be explained
that the strength increased without the deterioration of the ductility was attributed to the
microstructure refinement by the Er addition.
Effect of Silicon Addition and Thermal History on the Thermal Expansion Behavior of SiC/Al Composites
Authors: Zhang Qiang , Zhu Ye , Han Jie Cai , Wu Gaohui
Published: March 2009

Two Al-Si alloys (Al-12Si and Al-20Si) and an industrial pure Al were reinforced with
70vol.% dual-sized SiC particles. The composites experienced annealing treatment, to investigate the
effect of silicon addition and thermal history on the thermal expansion behavior of high SiC content
aluminum matrix composites. The results showed that silicon additions led to a beneficial reduction
in the coefficients of thermal expansion (CTEs) of the composites. In the temperature range between
20°C and 400°C, a continuous increase in CTEs with temperature was observed for SiCp/pure Al
composite. However, the CTEs of SiCp/Al-12Si and SiCp/Al-20Si showed the maxima at 350°Cand
250°C respectively, then diminished at higher temperatures. This was related to the change of solid
solubility of silicon in aluminum at elevated temperatures. The thermal expansion behavior of
SiCp/Al composites was also influenced by thermal history. After annealing treatment, the CTEs
were reduced when compared with those of as-cast composites. Annealing treatment reduced the
original thermal residual stresses, and then altered thermal expansion behavior of the composites.
Numerical Analysis of Nano- or Micro-Crystalline Materials during ECAP by Dislocation Evolution Method
Authors: Zhang Shao Rui , Chang Qun Feng , Li Da Yong , Peng Ying Hong
Published: March 2009

By the severe plastic deformation, the equal channel angular pressing method (ECAP) has
been used for producing metal materials with the ultra-fine grain size and specific mechanical
properties, in particular high yield strength. Analytical approaches have also been studied by few
researchers. However, none of the previous analyses have taken into account the strain hardening of
the material by considering the microstructure evolution. In this paper, the deformation behavior and
the strain harden of aluminum during equal channel angular pressing was calculated on the basis of a
dislocation evolution model. Then simulated stress, strain and strain distribution and strain hardening
were analyzed. The strain is seen to rapidly increase when the material passes the shear area. This
makes a maximum value of stress. And for the congregation of dislocation density, the maximal value
of strain increase with the process continuing.
Prediction of Fracture in Square-Cup Forming of Aluminium Alloy
Authors: Yu Zhong Qi , Lin Zhong Qin , Yang Yu Ying
Published: March 2009

Aluminum alloy sheet is becoming one of the main materials to take the place of steel
components to reduce the vehicle mass due to the advantage of low special density, high strength and
corrosion resistance. To predict the formability during the aluminium alloy sheet forming
accurately, , a ductile fracture criterion developed by the authors, was for numerical simulation, in
this paper. Fracture behavior in square-cup forming of the aluminium alloy LF21M was predicted by
means of the criterion. Comparison of the predicted results with experimental values shows that the
critical punch stroke and the fracture initiation position in square-cup forming of the aluminium alloy
have been predicted successfully by the criterion.