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To solve the difficulties associated with integral precise extrusion forming for complex components of magnesium alloy, Deform-3D finite element simulation software was used to conduct numerical analyses for the forming process. Different extrusion schemes were used for determining the overall extrusion difficulties associated with special-shaped thin-walled complex components of magnesium alloy. The effects of a preformed blank on the filling and formation of folding defects in the forming process were studied. Based on the principle of minimum energy in the process of plastic deformation and the law of least resistance, volume predistribution and equal distance flow quantitative compensation methods were put forward. These methods were used to optimize the size and structure of the preform, forming a uniform material flow distribution. They also enabled one to manifest a uniform material flow velocity distribution, reduce the forming load, and avoid the creation of folding and filling defects during the final forming, for the realization of an efficient and reliable preform optimization design for magnesium alloy profiled complex components. The results obtained from a forming test, microstructure and mechanical properties test showed that the mechanical properties of the extruded component all met the service indexes. This design method can provide a theoretical reference for preforming design of profiled complex components.

In this paper, a novel roll forming (RF) process is introduced. A kind of 120-mm projectile body with curved rotary profile is formed by the RF process. The RF process is compared with the traditional process of machine using the billet of draw. Based on the results, it can be concluded that the weight of billet reduces 28% by the presented process comparing with the traditional process and the reducing amount will increase with the increasing of the length of curved rotary profile. The presented process can use traditional draw press and has the same forming productivity. It also has the merits of lower forming force and machine time. The die of the present process is more complex and the manufacturing cost is higher than that of the traditional draw, but the die life of the present process is higher.

Hot deformation behaviors of the extruded AZ80 + 0.4% Ce magnesium alloy plate were investigated in the temperature range of 300–420 °C and strain rate range of 0.0005–0.5 s−1 by using a Gleeble 3500 thermal simulation test machine. The cylindrical specimens for hot compression tests were cut in 0°, 45° and 90° to the extruded direction of the plate, respectively. The microstructure analysis was carried out with optical microscopy (OM), X-ray diffractometry (XRD) and scanning electronic microscopy (SEM). The results showed that the flow stresses of the 0°, 45° and 90° specimens exhibited anisotropic behaviors, which weakened with increasing temperatures, strains, and decreasing strain rates. The processing maps of different specimens were calculated and analyzed according to the dynamic materials model. The optimized stability domains for all the three specimens were in the temperature range of 380–420 °C and strain rate range of 0.0005–0.005 s−1, while the instability domains varied with specimen orientations. The apparent activation energy of the 0°, 45° and 90° specimens were 154.45 kJ/mol, 129.16 kJ/mol and 145.97 kJ/mol, respectively, suggesting the change of deformation mechanisms with specimen orientations. The operation of different slip systems, which were indicated by the varying values of the Schmid factor, should be responsible for the anisotropic hot deformation behaviors for the extruded AZ80 + 0.4%Ce magnesium alloy plate with basal texture.

Obtaining consistent spectra by using different spectrometers is of critical importance to the fields that rely heavily on Raman spectroscopy. The quality of both qualitative and quantitative analysis depends on the stability of specific Raman peak shifts across instruments. Non-linear drifts in the Raman shifts can, however, introduce additional complexity in model building, potentially even rendering a model impractical. Fortunately, various types of shift correction methods can be applied in data preprocessing in order to address this problem. In this work, a moving window fast Fourier transform cross-correlation is developed to correct non-linear shifts for synchronization of spectra obtained from different Raman instruments. The performance of this method is demonstrated by using a series of Raman spectra of pharmaceuticals as well as comparing with data obtained by using an existing standard Raman shift scattering procedure. The results show that after the removal of shift displacements, the spectral consistency improves significantly, i.e., the spectral correlation coefficient of the two Raman instruments increased from 0.87 to 0.95. The developed standardization method has, to a certain extent, reduced instrumental systematic errors caused by measurement, while enhancing spectral compatibility and consistency through a simple and flexible moving window procedure.

3-D integration technologies have been of increasing interest for compact and high-performance system integration and packaging. Through-silicon-via (TSV) is one of the key technologies to enable vertical connections for stacked ICs and silicon packages. In the recent years, the annular via and taped via geometries have been the focus for industry research institutes and has been demonstrated to have lower electrical resistance and better thermal stability. Different TSV physical structures such as cylindrical, tapered, annular are analyzed using the FEM based EM simulator HFSS in this study. In addition to the TSV shape impact on the performance of TSV signal transmission, the effect of substrate conductivity on the signal transmission is investigated in this study.

Coiling temperature, finish rolling temperature and running speed of ZSAC1 strip during U-type cooling and number of valves which had been turned on were analyzed in order to find out the reason of low coiling temperature at tail of ZSAC1 strip in U-type cooling process. Results of research showed that running speed of strip and finish rolling temperature were main factors affecting accuracy of coiling temperature. Coiling temperature decreased with the increase of running speed of strip. Coiling temperature fluctuation would occur at the same part of strip when finish rolling temperature increased or decreased. Holding rolling speed and rolling temperature of strip stably can improve accuracy of coiling temperature during downstream U-type cooling.

In the present work, as-homogenized AZ80 alloy was subjected to the multi-pass compression at the same total compression strain and different compression passes. The effects of compression-pass on microstructure and mechanical properties were investigated. Results show that the intermittent reheating stage during the multi-pass compression process plays an important role in the microstructure evolution. During the intermittent reheating process, the fine grains in the duplex-grain microstructure generated by partial dynamic recrystallization grow rapidly, which lead to the increase of the average grain size and the decrease of the difference in grain size between the coarse and fine grains. This phenomenon is more obvious by the increase of the intermittent reheating stage. It finds that the hardness mainly depends on the average grain size, and the value decreases with the increase of the average grain size. However, the ultimate tensile strength and elongation mainly depends on the grain size distribution, and the better tensile properties can be obtained when the microstructure is more homogenous.

Cooking method of wheat straw pulp was investigated by microwave radiation at ambient pressure. In the microwave irradiation, wheat straw was cooked with mixed-alkali at normal pressure. The optimum process conditions determined by single-factor and orthogonal experiments were provided as follows: total alkali content was 16%, the ratio of solid to liquid was 1:6,and microwave irradiation time was 45min. Paper performance tests was run and showed that the index was equal or better than those produced by conventional methods. A consistent yield (around 60.1%) of wheat straw pulp was observed after repeated experiments.

The new application of YMnO3 as a high near-infrared (NIR) reflective inorganic pigment has been developed. Single-phased perovskite nanocrystalline YMnO3 samples with different average sizes have been synthesized through a polyacrylamide gel route. With the calcination temperature increasing from 700 °C to 900 °C, the color of the samples is blue-green, and the broad band value decreases from 1.89 to 1.58 eV due to the O2p–Mn3d charge-transfer transition. The NIR reflectance and solar reflectance values of corresponding pigmented coating increase from 51.4% to 53.4% and from 23.9% to 32.5%, respectively, which are higher than that of commercially available roofing products of the same color. The prepared YMnO3 pigment can be well served as colored “cool colorant”.

By multi-axis active load deformation method, the equivalence diameter tee joint was formed on multi-axis numerical control hydraulic press machine. The loading route was determined by numerical simulation. The experiment results showed that two loading method can complete form the parts. The different directions metal flow was observed under multi-axis loading conditions. To simplify analysis, the flow field was divided into several regions. In every region, the metal flow direction was only one. In multi-axis loading, the way of deformation follows priority deformation principle: The metal flows only choose one direction even if the work piece were under the complicated coupling field condition. The mathematical model of the deformation force and metal flow rate was established. The theoretical calculation had been provided.

Quantities AZ80 magnesium alloy billets were compressed with 60 % height reduction on hot process simulator at 473, 523, 573, 623, 673, 723 K under strain rates of 0.001, 0.01, 0.1, 1 and 10 s-1. In order to predict the occurrence of surface fracture, the critical damage factor based on the Cockcroft-Latham equation were obtained by analysing the results of the corresponding finite element calculation. The results show that the critical damage factor at 523, 573, 623, 673 K under strain rates of 0.001, 0.01, 0.1 and 1 s-1 is not a constant but varies in a range from 0.1397 to 0.4653. Meanwhile, a constitutive model with a few parameters is used to characterize the dynamic recrystallization strain softening of AZ80 alloy, which comprehensively reflect the effects of the deformation temperature, strain and strain rate on the flow stress.

This paper presents the results of an investigation of the effects of homogenizing heat treatment and extrusion on plasticity of the as-cast AZ80 magnesium alloy. Both the homogenized and non-homogenized billets of AZ80 alloy were forward extruded at several different temperatures and different extrusion ratios. The effects of homogenization and extrusion on plasticity were evaluated by conducting tensile tests on these billets at room temperature and comparing their elongations. The experimental results showed that the elongation of the as-cast AZ80 alloy was increased by 67% after the homogenization treatment. After extrusion, the elongation of both the homogenized and non-homogenized AZ80 alloy increased significantly. The elongation of the homogenized billets decreased gradually with increasing temperature. For the non-homogenized billets, however, the elongation decreased sharply with temperature from 300 to 350 °C and then increased gradually with increasing temperature. There was not clear correlation between the elongations of both the homogenized and non-homogenized billets and the extrusion ratio.

The Co1-xNixCr2O4(x=0.1, 0.2 and 0.3) solid solutions were successfully synthesized by low-temperature combustion synthesis method. The crystal structure and optical properties of the samples were investigated. The samples displayed single phase spinel structure with 30 nm in grain size. Infrared absorption peaks at about 525 and 630 cm-1 corresponded to the vibration of octahedron group ([CrO6] / [NiO6]) and tetrahedron group ([CoO4] / [NiO4]) respectively. Due to the electronic transition of 4A2(F) → 4T1(P) of Co2+, 4A2g → 4T2g of Cr3+, 3T1g(F) → 3T1g(P) and 3A2g(F) → 3T1g(F) of Ni2+, absorption peaks at about 578, 618 and 670 nm were observed in the visible region, making the color center be green. The degree of lightness, greenness and chroma increased, whereas the degree of blueness decreased, making the color of the samples transit from pale green to brilliant green as x value increased.

Power short (PS) bin failure due to Al bridging in bond pad regions originated from Al whisker, caused severe yield loss in advanced technology nodes. A comprehensive study on circuit design impact on Al whisker bridging issue was carried out and it was found that increasing Al metal spacing reduced Al whisker bridging. Furthermore, through optimization of process, the novel Al high power deposition recipe demonstrated that power short failure caused by Al whisker could be completely eliminated. The two proposed solutions provide a guideline to solve Al whisker for more advanced technology nodes.

The (C60)n@SWNT (peapod) samples were prepared by vapor diffusion method. We performed the high pressure Raman measurements on the peapod samples by using a Mao-Bell type diamond anvil cell (DAC). In the In situ high pressure experiments, the peapod samples were exposed under UV laser line irradiation. The polymerization of C60 molecules in SWNT cave under both laser irradiation and pressure effects has been studied. The Raman spectra of the released samples from high pressure indicated that C60s form one-dimensional orthorhombic polymer. For the Raman measurements, two different excitation wavelengths were used, 325 nm laser and 830 nm laser.

The influences of solution treatment, deformation strain, and nanometric Al2O3 particulate on dry wear properties for nanometric Al2O3 particulate reinforced Al alloy matrix Composites manufactured by casting were investigated. The result showed that both the wear resistance of AL matrix and the composites increased rapidly with increasing solution temperatures. The wear resistance increased slightly with increasing deformation strain for the composites. The wear resistance of the composites is higher than the AL matrix after the same deformation and heat treatment. Microstructure observation revealed that the grain sizes of the composites increased with increasing solution temperature and decreased with more severe deformation. Abrasive wear was the main wear mechanism both for the AL matrix and the composites.

In order to study the effect of plastic deformation on microstructure and mechanical properties of as-cast AZ91 magnesium alloy, experiments of hot direct extrusion were performed at different extrusion temperatures and different extrusion ratios. The microstructure and mechanical properties of extruded billets and extrudate were measured. Experimental results show that the grain size of as-cast AZ91 magnesium alloy can be dramatically refined by extrusion. Hot extrusion can obviously improve the mechanical properties of as-cast AZ91 magnesium Alloy, comparing with the pre-extruded billet, the tensile strength, yield strength and elongation of extrudate can be improved by at least 69%, 117% and 150% respectively. As the extrusion temperature increases, the tensile strength and yield strength of extrudate will increase. As the extrusion ratio increases, the tensile strength and yield strength of extrudate will increase at first and then fall. At the time of extrusion temperature of 420°C and extrusion ratio of 45, the highest tensile strength of 381Mpa and yield strength of 303MPa can be achieved for the extrudate.

In the paper, the high-temperature compression test of BTi-62421S alloy was carried out in the temperature range from 850°C to 1050°C, strain rate range from 0.01 s-1to 30 s-1, and the deformation of 70%. The results show that the flow stress of BTi-62421S alloy significantly increased with the decreasing of the temperature and the increasing of the strain rate. By calculating the activation energy of deformation and analyzing the stress-strain curve, it can be seen that the softening mechanism of hot deformation of BTi-62421S alloy is different near the （α+β）/β phase transforming temperature. The softening mechanism of hot deformation is mainly dynamic recrystallization in （α+β） area and it is mainly dynamic recovery above β phase transforming temperature. According to hyperbolic sine model, the alloy’s constitutive equation is established. Key word: BTi-62421S alloy; high temperature figuration; constitutive equation

Four main ingredients of the dust and four material corona electrodes were selected from sintering machine electrostatic precipitator (ESP) in this paper, affinity differences of the corona electrode with the four kinds of dusts can be concluded from the experiment on the condition of low voltage. According to the composition of dust to be processed in actual production, corresponding corona electrode and collecting plate materials should be selected to improve the phenomenon of corona electrode surface mast and tip balling and to improve collection efficiency.

Quantities AZ80 magnesium alloy billets were compressed with 60% height reduction on hot process simulator at 200,250,300,350,400,450°C under strain rates of 0.001, 0.01, 0.1,1 and 10s-1.The processing maps based on the Dynamic Material Modeling (DMM) were constructed, which is useful to analyze the deformation mechanism and the destabilization mechanism of AZ80 alloy. If the mechanical property of AZ80 alloy is taken into consideration, the optimal deformation processing parameters from the processing maps are the deformation temperatures ranging from 300 to 350°C and strain rates ranging from 0.001 to 0.01s-1. Meanwhile, a flow stress model with eight parameters is used to characterize the dynamic recrystallization strain softening of AZ80 alloy.

Quantities AZ80 and AZ31 magnesium alloy billets were compressed with 60% height reduction on hot process simulator at 150,200,250,300,350,400,450°C under strain rates of 0.001, 0.01, 0.1,1 and 10s-1.A constitutive model with a few parameters is used to characterize the dynamic recrystallization strain softening of AZ80 and AZ31 alloy, which comprehensively reflect the effects of the deformation temperature, strain and strain rate on flow stress.

In this paper, rigid plastic finite element method simulation of AZ31 wrought magnesium alloy radiator isothermal extrusion is studied according to the stress - strain data of magnesium alloy obtained from isothermal compression experiments and the mathematical model of warm forming by the regression. And the paper focuses on the AZ31 magnesium alloy during isothermal extrusion, the deformation force and metal flowing law. The simulated stress field, strain field, velocity field, load changes and so on from simulation can predict the defect in deformation, and offer the reliable reference basis for such parts processing in isothermal extrusion.

Foamed aluminum has been recently developed as one of new structure functional materials due mainly to its excellent properties such as energy absorption property. It is significant to investigate the compressive behavior and energy absorption property of foamed aluminum under the condition of static and dynamic loading. The compressive deformation behavior of foamed aluminum with open pore structure was experimentally studied and the effects of the porosity, the type of materials, the pore size and the sample size were discussed in detail by means of the orthogonal experiments. The results showed that the type of materials had the most evident influence on the compressive property of foamed aluminum among the factors investigated, and that the size effects of the experimental results were observed.

Aluminum alloy 7A04 compressed at high deformation temperature and large deformation is applied in two different heat treatment (T5 and T6), then microstructure and properties of the alloy after heat treatment are investigated. The mechanical properties are studied by means of the tensile testing and the hardness testing. The microstructure characteristics and the fractorgraphy analysis are respectively investigated with optical microscopy and SEM. The experimental results indicate that after T6 heat treatment, the second-phase particles dispersed in the matrix, which can efficiently improving the strength of the alloy, but reduced the toughness. After T5 heat treatment, the coarse and discontinuous second-phase is distributed along the grain boundary, which can lead to the low strength and high toughness because of the lack of the strengthening phase in the grains. The fracture appearance is intercrystalline fracture after T6 heat treatment, and dimple transgranular fracture after T5 heat treatment.

Nanometric Al2O3 particulate reinforced Al alloy Composites bar manufactured by casting were hot compressed to 20% of its height, and solution treated at temperatures of 480°C, 490°C 510°C for 3 hours, then aged at a temperature of 120°C for 24 hours. Wear properties and hardness were investigated by wear tester and durometer, and microstructures were observed by optical microscopy. The result shows that the hardness of Al2O3 particulate reinforced Al composites increases with increasing solution temperatures, while wear loss and friction coefficient decreases with increasing solution temperatures. Microstructure observation revealed that the Al2O3 particulate reinforced Al alloy Matrix composites is of lamellar grain structure and the grain size increases with increasing solution treatment temperatures.

Mechanical property tests of AZ31magnesium alloy sheet were carried out with compressive axis 0°，45° and 90° from normal direction respectively using Split Hopkinson Pressure Bar (SHPB). The results showed that the strain hardening rate for both 0° and 90° specimen decreases with increasing strain, and remain a constant approximately for 45° specimen at a strain rate of 2.8×103s-1. The flow stress of 45° specimen is the lowest compare with the other two specimens. Twined area fractions (TAF), dislocation multiplication and twinning system were characterized using optical microscopy (OM) and transmission electron microscopy (TEM). The results revealed that TAF for both 0° and 45° specimens are far less than 90° specimen at the same strain. Microstructure observation for specimens at a strain of 0.003 shows that dislocation multiplications for 0º specimen are far less than 45° specimen, and that {10-12}twinning，{10-11}-{10-12}double twinning and twin intersection of vast amounts are activated for 90° specimen. Dynamic mechanical property anisotropy can be explained based on different microstructure evolution and plastic deformation mechanisms.

The precipitation mechanism of secondary-precipitated phase β in AZ80 magnesium alloy during the hot compression deformation under different temperature was investigated. The results show that there are β-Mg17Al12 phases with different morphology and precipitation mechanism in the microstructure of AZ80 alloy deformed both in two-phase region、critical region and single-phase region. β-Mg17Al12 phases were directly deformed and broken to be strip form during the compression under 200、250、300 and 350°C. A lot of fine granular second phase particles precipitated with the grain refinement simultaneously in AZ80 alloy deformed in two-phase region with tremendous deformation. There are also fine granular second phase particles precipitated in the alloy deformed in critical region. There are massive β-Mg17Al12 phases precipitated in the alloy deformed under higher temperature such as 350 and 400°C during the water cooling after the compression, the high power observation of which is fine and tightly lamellar microstructure. Compared with coarse reticular β-Mg17Al12 phases in the as-cast microstructure of AZ80 alloy, the morphology of β-Mg17Al12 phases precipitated during the hot compression has obvious improvement.

Dynamic mechanical properties of AZ31 magnesium alloy plate were carried out using split Hopkinson pressure bar (SHPB) with compression direction 0° and 90° from normal direction respectively. Optical microscopy (OM) and scanning electronic microscopy (SEM) were used for the observation of microstructure and fractograph. OM observations showed that cracks initiated and propagated along localized deformed bands consisted of twin intersection for 0° specimen, and that cracks initiated and propagated along localized transformed bands consisted of fine equiaxed dynamic recrystallized grains for 90° specimen. SEM observations showed that the fractograph exhibited typical ductile dimple fracture pattern for 0° and 90° specimens due to the thermal accumulation in localized bands caused by severe plastic deformation. The fracture mechanisms are anisotropic for AZ31 magnesium alloy plate, which contributed to the dynamic mechanical anisotropy of AZ31 magnesium alloy plate.

The forward extrusion experiments of homogenized AZ80 magnesium alloy were conducted in the extrusion temperature range of 300°C to 420°C and extrusion ratios between 15 and 75 to study the effect of plastic deformation on the mechanical properties and microstructure. The microstructure and mechanical properties of extrudate were measured by tensile tests and optical microscopy. The results demonstrated that the alloy grains were small, and small amounts of black hard and brittle second-phase precipitated at 330°C. When the extrusion temperature was up to 390°C, the grain size increased significantly, but the second phase precipitation became continuous. And then, in the case of the extrusion ratio of 60, the tensile strength of the alloy reached the peak value of 390 MPa. Inhomogeneous precipitation of the second-phase increased with the increasing of extrusion temperature. At the same temperature, the tensile strength increased firstly and then decreased with increasing extrusion ratio. With the gradual increase of the grain refinement, the dispersed precipitates increased and the tensile strength and plasticity reached their peaks when the extrusion temperature was 390°C. As the grain grew, the second phase distribution became inhomogeneous, and the strength and plasticity gradually decreased.

Aluminum (Al) coating was thermally sprayed on the surface of AZ80 magnesium (Mg) alloy. The Al-coating was deformed at 400°C with different deformation degrees of 15%, 30%, 45%, 60% and 80%. The corrosion properties of the AZ80 Mg alloys coated with Al-coatings were studied by potentiodynamic and galvanic tests in 3.5% NaCl solution; the adhesion strengths between Al-coatings and AZ80 substrate were also measured simultaneously by tensile test. The results showed that, Al-coating could decrease the corrosion rate of AZ80 Mg alloys, and the corrosion rate was related not only with the density of Al-coating but also with the adhesion strength of Al-coating. Before the formation of dense Al-coating, the corrosion rate of Al-coated AZ80 Mg alloys decreased with the increasing of bonding strength of Al-coating; after the formation of dense Al-coating, the corrosion rate of Al-coated AZ80 Mg was mainly determined by the structure of Al-coating. It was also revealed that with the increasing of deformation degree, the corrosion rate of the Al-coated AZ80 Mg alloys first decreased then increased, while the adhesion strength increased gradually. The corrosion rate of AZ80 Mg alloy coated with 60% deformed Al-coating was the lowest, which was only 19% of that of the AZ80 substrate.

Direct extrusion forming process, two-stage extrusion forming process and composite extrusion forming process were designed for manufacturing a titanium alloy tapered piece. Comparison of the forming loads under the different processes were investigated using Deform finite element method(FEM).Considering the load size, energy consumption and production efficiency, the best extrusion forming process was eventually selected. The result showed that: In the direct extrusion forming process, the maximum load was 11.5MN, and the die life was short; In the two-stage extrusion forming process, the maximum load was only 4.25MN, but it had a poorer effectiveness and higher energy consumption because of two-stage forming processes. In the composite extrusion forming process, the maximum load was only 38.6% of direct forming process, and it had a higher effectiveness and lower energy consumption because of one-stage forming processes.

Hot compression tests of 7075 aluminum alloy were carried out on the Gleeble-1500 thermal simulation machine at strain rates of 0.1s-1 ，1 s-1 and at temperatures of 320°C,400°C,480°C. The compression direction are aligned at 0°，45°and 90°to the axis direction of the bar. Microstructure was studied using Optical Microscopy. The results show that the true stress of all three specimen increases with the decrease of temperature and the increase of strain rates. The true stresses rose rapidly to peak value and then held constant or decreased with the increase of the true strains at different deformation conditions. The yield strength of the specimens in 0° to the axis direction is higher than that of 90°, and 45° specimen has the lowest yield strength at different deformation conditions, which could be attributed to the elongated grain structures of the bar.

The influence of temperatures and passes on hot extruded 7075 Al bar were investigated using hydraulic press. The microstructures were observed using optical microscopy. The results showed that the as received AL bar consists of lamellar grain structures, and that equiaxed mixed grain size were observed with different passes at 320°C. Continuous dynamic recrystallization (CDRX) is responsible for the formation of small grain. The large grain tends to increases with more passes due to longer holding time. CDRX were observed for one pass only at 480°C. Lamellar grain structures were formed with different passes at 480°C.The lamellar grain structures are aligned at 50° to 70° to compression direction from one pass to four passes.

In the present research, the influences of different extrusion ratios (15, 30, 45, 60, and 75), extrusion temperatures (300 , 340 , 380 , 420 , and 460 ), and subsequent heat treatment on the mechanical properties and microstructure of as-cast ZK60 magnesium alloy have been investigated through the tensile tests and via metallographic observation. The results show that forward extrusion process can refine the microstructure of as-cast ZK60 alloy effectively. If as-cast ZK60 alloys have been extruded with the extrusion ratio 45 at 380 ,420 and 460 , respectively, and then post-heat treatment was conducted, the ZK60 alloy’s strength is higher under T5 than T6 treatment. For as-cast ZK60 alloy processed by extrusion and T5 method, the most appropriate temperature for extrusion processing is 300 , at which its tensile strength are highest provided the extrusion ratio is 30 but yet its plasticity is best provided the extrusion ratio is 45. If forward extrusions were conducted at 380 , mechanical properties of ZK60 alloy have little difference as the extrusion ratio varies. When T6 treatment was conducted for the extruded bars, their mechanical properties were improved little, moreover, the bigger the extrusion ratio is, the higher the tensile strength and elongation of the extruded bars become.

In the present research, the influences of different extrusion ratios (15, 30, 45, 60, and 75) and extrusion temperature (300°C, 330°C, 360°C, 390°C, 420°C) on the mechanical properties and microstructure changes of AZ80 magnesium alloy have been investigated through tensile test and via ZEISS digital metallographic microscope observation. Research indicates that the alloy’s plasticity gradually decreases as the temperature increases, and that the alloy’s tensile strength varies with the extrusion ratio. At 330°C, the alloy’s particle grain is small and a small amount of black hard and brittle second-phase β (Mg17Al12) are precipitated uniformly along the grain boundary causing the gradual increase of the alloy’s tensile strength. When the extrusion temperature is up to 390°C, the grain size increases significantly, but the second phase precipitation along grain boundaries transforms into continuous and uniform-distribution precipitation within the grain. In this case, when the extrusion ratio is 60, the alloy’s tensile strength reaches its peak 390 Mpa. As the extrusion temperature increases, inhomogeneous precipitation of the second-phase along grain boundaries increases, causing the decrease of the alloy’s strength. At the same temperature, both the tensile strength and plasticity increases firstly and then decreases as extrusion ratio increases. With the gradual increase of the refinement grain, the dispersed precipitates increase and the alloy’s tensile strength and plasticity reach their peaks when the extrusion temperature is 390°C. As the grain grows, the second phase becomes inhomogeneous distribution, and the alloy’s strength and plasticity gradually decrease.

In the present paper a research has been made on the effect of aging on the microstructure and mechanical properties of AZ80 and ZK60 wrought magnesium alloys by virtue of optical microscope, electronic scanning microscope and mechanical testers. The research indicates that both the tensile strength and elongation of AZ80 alloy first increase and then decrease as the aging temperature rises, and that, at 140°C-170°C aging temperature, the alloy has good performances in both tensile strength and elongation, they both reaching their peak values at 170°C aging temperature. It has been proved in these researches that while the hardness of ZK60 alloy first increase and then decrease as the aging temperature rises and that the hardness reaches its peak value at 170°C aging temperature, the impact of toughness of the alloy is just the opposite. ZK60 alloy has good performances in both impact toughness and other properties at 140-200°C aging temperature. Constrastive researches have shown that, at the same aging temperature, ZK60 alloy has a better performance than AZ80 alloy.

The effects of extrusion ratios (15, 30, 45and 60) on microstructure and mechanical properties of ZK60 magnesium alloy after T5 treatment were investigated. The results show that mechanical properties increase with the increase of extrusion ratios from 15 to 45．However, when the extrusion ratio is increase to 60, each mechanical property is decreased severly．By comparison，in the extrusion ratio of 30, ZK60 magnesium alloy after T5 treatment has excellent comprehensive mechanical properties．Different degrees of dynamic recrystallization appeared in the extrusion process and induced precipitation of second phase．The precipitation of the second phase is beneficial to the grain refinement and meanwhile to the promotion of the strength．

With the deformation temperature between 250°C and 450°C as well as the strain rate between 0.01s-1 and 5s-1, the hot compression tests of AZ80 magnesium alloy were performed on Gleeble-3800 thermal simulation testing machine, so as to seek out the responses of mechanical behavior of AZ80 magnesium alloy under different deformation conditions. The results indicated that AZ80 magnesium alloy shows dynamical recrystallization when hot compessed, the recrystallization is prone to happen and the stress peak decreases with the temperature increased, and the critical strain to produce the transformation of recrystallization augments with the strain rate increased.

NiCoCrAlTaY bond coat was deposited on pure nickel substrate by low pressure plasma spraying(LPPS), and ZrO2-8%Y2O3 (mass fraction) nanostructured and ZrO2-7%Y2O3 (mass fraction) conventional thermal barrier coatings(TBCs) were deposited by air plasma spraying(APS). The thermal shock behaviors of the nanostructured and conventional TBCs were investigated by quenching the coating samples in cold water from 1 150, 1 200 and 1 250 °C, respectively. Scanning electron microscopy(SEM) was used to examine the microstructures of the samples after thermal shock testing. Energy dispersive analysis of X-ray(EDAX) was used to analyze the interface diffusion behavior of the bond coat elements. X-ray diffractometry(XRD) was used to analyze the constituent phases of the samples. Experimental results indicate that the nanostructured TBC is superior to the conventional TBC in thermal shock performance. Both the nanostructured and conventional TBCs fail along the bond coat/substrate interface. The constituent phase of the as-sprayed conventional TBC is diffusionless-transformed tetragonal(t′). However, the constituent phase of the as-sprayed nanostructured TBC is cubic(c). There is a difference in the crystal size at the spalled surfaces of the nanostructured and conventional TBCs. The constituent phases of the spalled surfaces are mainly composed of Ni2.88Cr1.12 and oxides of bond coat elements.

The plasticity of AZ31 and ZK60 magnesium alloys was studied by means of hot compression deformation tests on Gleeble 1500D machines at different temperatures and strain rates. The results indicate that the thermal simulation curves of AZ31 and ZK60 have different forms under the same deformation condition. The general curves of AZ31 have the character of dynamic recrystallization that the flow stress increases to a peak and then decreases to a steady state. Most deformation curves of ZK60 have the obvious character that around 0.2 in strain the stress reaches the peak and declines rapidly to the lowest, while the other curves have the character of dynamic recrystallization. From the analysis, a deformation temperature should reasonably be selected from 250 °C to 400 °C for AZ31, while it was concluded to be 200 °C or 400 °C for ZK60.

High pressure valve always takes several dozens to several hundreds MPa pressure and which was difficulty to form because of its complex internal structure. In this paper, three-dimensional numerical simulation was carried out to investigate metal flow behavior during the three-way valve extrusion process. The block shape materials were formed to shell shape three-way components by the level and vertical direction uniform temperature simultaneous extrusion. The simulation results show that the metal flows were influenced by both loading sequence and time of the moving die of two directions. The loading process worked out through dynamic simulation can guide the actual processing.

Thermal compression tests of AZ61 magnesium alloy was performed at deformation temperature 150-400°C and strain rates ranged from 0.01s-1 to 10s-1, and the microstructure were observed for deformation specimens. The result shows that dynamic recrystallization (DRX) was happened under the center warm deformation condition for AZ61 alloy. The values of stress peak decrease when the deformation temperature increase, the grain size grows up at the same time. On the other hand, the critical strain increase and the grain size get smaller with the strain ratio increasing. Therefore temperature and strain ratio can make a great effect on the microstructure and mechanical properties of AZ61 alloy, but temperature is a more important factor.

Numerical simulation and experimental studies on metal flow were carried out during the forging process of AZ80 magnesium alloy wheel to evaluate the formahility and to determine the tool radius. Tool radius of R15mm, R20mm and R30mm were used during forging the front lip. Using the properties established based hot compression tests result, the finite element simulations were conducted at various tool radiuses to determine forming behavior of magnesium alloy. The simulation results show that the heavy folding defect resulted from the smaller tool radius of 15mm and 20mm. Improved formability was achieved when tool radius is 30mm. The forging trials were performed at design improvement using designed experimental equipment. The AZ80 magnesium alloy wheel was forged successfully at suitable process parameters. The experimental results were in reasonable agreement with the numerical simulation.

Warm compression tests of AZ31 Mg alloy were carried out at five temperatures in 30°C intervals from 210°C to 330°C. The samples of different thickness which were machined from as-cast and pre-strained AZ31 billets were compressed into thickness 1mm and then cooled in the air to room temperature. The microstructural evolution of AZ31 Mg alloy was investigated during warm compression forming. The results show that all the samples have undergone a microstructure changes to different scales in the range investigated. The twinning is the predominant deformation mechanism for magnesium alloys at moderate temperatures and its occurrence is dependent on temperature and strain. Microstructural evaluation indicates that the mean size of the recrystallised grains decreases with increasing effective strain and temperature because of sufficient dynamic recrystallization. The original grain has significant influence on microstructural evolution during warm forming.

The graded multiweb structure of heterogeneous anisotropic materials, which makes full use of the continuous, gradual and changing physical mechanical performance of material properties, has a widespread application in aeroplane aerofoil structure and automobile lightweight structure. On the basis of laminate buckling theory, the equivalent rigidity method is adopted to establish the corresponding constitutive relation and the non-linear buckling governing equation for the graded multiweb structure. In finding the solution, the critical load of buckling under different complicated boundary conditions together with combined loads were obtained and testification of the experimental analysis shows that the calculation results can satisfy the requirements of engineering design in a satisfactory way. Results obtained from the research say that: graded materials can reduce the concentrated stress on the interface in an effective way and weaken the effect of initial defect in materials and thereby improve the strength and toughness of materials.

In order to study the warm forming strengthening behaviours of AZ31 magnesium alloy, plane strain compression tests were carried out at the temperatures ranged from 210 to 330°C for as-cast and pre-forged Alloys. Tensile specimens were machined from the compressed samples. Room temperature mechanical testing was conducted according to the specifications. Microstrutres were investigated using scanning electron microscope. The analysis revealed that there is an excellent warm forming strengthening effect for as-cast AZ31 alloy with hexagonal close-packed structure. The increments of the tensible strength is about 40～50%. With decreasing temperature, the tensible strength increases during warm forming. The deformation extent and deformation mode has its different influence on strengthening effect. The high strength was attributed to the fine-grain strengthening and work hardening. This suggests that fine grain and high strength are attained for AZ31 alloy by means of rational combined action of work hardening and fine-grain strengthening during warm forming.

Split Hopkinson Pressure Bars (SHPB) was applied to investigate shock resistance of magnesium alloy. The deformation behaviour was reported of ZK60 magnesium alloy at high strain rate, and the relationship was established between the dynamic properties and the impact velocity. Results indicate: with impact velocity improvement, much twinned crystal and fine grain can be obtianed, this made dynamic properties enhancement of ZK60 alloy.

This paper presents a theoretical analysis for the various kinds of buckling behaviour of infinitely long laminated cylindrical shallow shells subjected to lateral uniform pressure. The exact solutions of the nonlinear equilibrium equations, in which first-order shear deformation is included, are obtained and the buckling criteria corresponding to different kinds of buckling are constructed taking into account the effects of the transverse shear deformation.

A low absorptivity broadband negative refractive index metamaterial with a multi-gap split-ring and metallic cross (MSMC) structure is proposed and investigated numerically and experimentally in the microwave frequency range. The effective media parameters were retrieved from the numerical and experimental results, which clearly show that there exists a very wide frequency band where the permittivity and permeability are negative. The influence of the structure parameters on the magnetic response and the cut-off frequency of the negative permittivity are studied in detail. This metamaterial would have potential application in designing broadband microwave devices.