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The aim of this work was to analyze the recrystallization behavior of cold rolled Aluminum/graphene composites during annealing. The Aluminum/graphene composite was cold rolled firstly, and then annealed at different temperature (250°C, 300°C, 350°C, 400°C) and for various time (1 h, 2 h, 8 h, 32 h). Full recrystallization did not occur until the annealing temperature was above 300 °C. With annealing temperature increasing from 250 to 300°C, the hardness of the composites decreased from 49.6 to 27.6 HV. Grain growth were not observed at high annealing temperature and longer annealing time, which suggested that Graphene has strong pinning effect on the grain boundary of Aluminum.

Partial transient liquid phase (PTLP) bonding of TiC cermet to 06Cr19Ni10 stainless steel was carried out. Impulse pressuring was used to reduce the bonding time, and a Ti/Cu/Nb interlayer was employed to alleviate the detrimental effect of interfacial reaction products on the bonding strength. Successful bonding was achieved at 885 °C under a pulsed pressure of 2–10 MPa within durations in the range of 2–8 min, which was notably shortened in comparison with conventional PTLP bonding. Microstructure characterization revealed the σ phase with a limit solubility of Nb, a sequence of Ti—Cu intermetallic phases and solid solutions of Ni and Cu in α+β Ti in the reaction zone. The maximum shear strength of 106.7 MPa was obtained when the joint was bonded for 5 min, indicating that a robust metallurgical bonding was achieved. Upon shear loading, the joints fractured along the Ti—Cu intermetallics interface and spread to the interior of TiC cermet in a brittle cleavage manner.

The microstructure of pre-aged AA7085 rolled plate was studied by means of hardness tests, optical microscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction and electrical conductivity tests. The results show that supper refined and homogeneous precipitates were formed during pre-aging, but the hardness of the alloy was still relatively low. There occurred a large number of dislocations when the warm deformation was introduced, and the size of the intragranular precipitates firstly increases and then decreases and then increases with the dislocation density increasing, which was caused by the role of dislocations on inhibiting the formation of GP zone and promoting the nucleation and transformation ofηphase. Meanwhile, the distribution of grain boundary precipitates also changed from continuous chain to coarsening interrupted distribution and the precipitate free zone (PFZ) broadened obviously.

A new Al-Mg-Si-Cu aluminum alloy was hot compressed at temperatures between 320°Cand 530°Cand strain rates between 0.001 s1and 10 s1using a Gleeble-1500 thermo-simulation machine. The effects of deformation heating on flow stress were analyzed and corrected, and a comparison was made of hyperbolic-sine constitutive equations with and without correction. The results show that the deformation heating apparently increases the flow stress at strain rates of 1 s1, 10 s1. The thermal activation energy values were 325.12 KJ/mol and 304.47 KJ/mol before and after correction, respectively.

The high strength of Mg-Y-Nd alloy has been achieved primarily by precipitation hardening. Therefore, it is important to investigate the influence of various precipitate phases on the tensile properties of Mg-Y-Nd alloys. In this study, an extruded Mg-Y-Nd alloy was aged at various temperatures to examine the hardening behaviors. The results showed that the as-extruded alloy exhibited remarkable age hardening response at 210°C due to the precipitation of β’, and slight hardening response at 150°C and 280°C due to the precipitation of β’’ and β, respectively. Furthermore, different precipitates exerted different effects on the tensile properties. In comparison with the as-extruded alloy, the yield strength of the alloys aged at 210 °C and 150 °C was increased by 21 MPa and 8 MPa, respectively, whereas the yield strength of the alloy aged at 280°C was decreased by 30 MPa. The elongation of the alloy aged at 210°C and 150°C was also largely reduced by 3.4% and 2.9%, respectively, while the elongation of the alloy aged at 280°C was only slightly reduced (6.3%). Moreover, compared with the as-extruded alloy, the alloy aged at 210°C and 150°C exhibited lower hardening capacity and higher strain hardening rate at the initial stage, but the strain hardening rate decreased more quickly with the increasing stress. The alloy aged at 280°C exhibited similar strain hardening behavior with the as-extruded alloy. The results in this study provide guidelines for determining the heat treatment parameters for the Mg-Y-Nd alloys to improve their tensile properties.

Uni-axial tensile plastic deformation behavior of rolled magnesium alloy AZ31B under the temperature range from room temperature(RT) to 250°C with strain rates between 10-3 and 10-1s-1 has been systematically investigated. Microstructure evolution and texture were determined using optical microscopy (OM) and electron back-scattered diffraction (EBSD) techniques, respectively. Our results indicated that the strength and elongation-to-fracture were more sensitive to strain rates at elevated temperature rather than that at room temperature; dynamic recrystallization (DRX) and relaxation of stress at elevated temperature resulted in dramatic change of mechanical properties. Compared with strain rate, the temperature played a more important role in ductility of AZ31B Mg alloy sheet.

In this paper, the influence of clock rolling（CR）on microstructure and texture as well as the anisotropic properties of AZ31 alloy sheet was systematically studied. Compared to unidirectional rolling（UR）, clock rolling leads to more uniform microstructure in annealed sample. The average grain sizes of the two kinds of sheet are similar. Texture measurement reveals that clock rolling can effectively weaken the intensity of basal texture and generate more symmetrical basal texture. Clock rolled samples exhibit weaker anisotropy of mechanical properties due to its lower basal texture intensities and more symmetrical basal texture in tensile test.

This paper describes the development and design of a novel short stress path rolling mill which is used for teaching and research. The rolling mill can implement the asymmetric rolling by the way of the adjustment of upper roll speed, and also working as conventional rolling when the roll speeds of two rolls are equal. The rolling mill can produce not only the plate and sheet, but also profiles by the roll of different grooves. The rolling mill is appropriate for the rolling of the steels and nonferrous metals. In this paper, the design ideas and main parameters of principal components are presented with respect to the new rolling mill. It can provide references for the design and manufacture of rolling mill of similar functions and structures.

Single cold rolling and double cold rolling were applied to hot rolled strips with different reduction ratios. The evolutions of {100}, {111} and Goss face texture during double rolling were investigated by comparing the orientation distribution function (ODF) of the double rolled sample with that of the single rolled one. The double cold rolling texture is characterized by a higher γ-texture and a lower α-texture, and the {111} component is improved remarkably. Based on the TEM observation and mechanical properties test, it is found that the reduction ratio assignment significantly affects the texture variation, as-annealing microstructures, and properties of the double cold rolled samples. These results may provide a theoretical guide for the industrial production of double cold rolled IF steel.

The magnesium alloy sheets have poor plasticity and formability due to their strong (0002) basal texture. In this paper a new method, repeatedly unidirectional bending (RUB), was used to improve formability of the magnesium alloy sheets. The samples were deformed repeatedly by the unidirectional bending at room temperature and annealed. Firstly, RUB route which is the most infection to formability was investigated. There were two RUB route, single surface RUB and reserve surface RUB. The result showed that better formability can be obtained by the reserve surface RUB. Focused on the development of formability of magnesium alloy sheet, the technological parameters, such as RUB passes, radius of support, annealing temperature and holding time, were determined by orthogonal experiment,and hence the optimal RUB process was acquired. Mechanical property of the samples before and after RUB were characterized and compared. After RUB, (0002) basal textural component of cold rolled magnesium alloy sheet was weakened and σb, σ0.2 decreased obviously. The Erichsen values can be considerably enhanced from 3.53mm to around 6.0mm through RUB.The samples were deformed repeatedly by the unidirectional bending at room temperature and annealed. Firstly, RUB route which is the most infection to formability was investigated. There were two RUB route, single surface RUB and

The AZ31 thin sheet (minimum thickness less than 1mm) was obtained by rolling the cast strip which was prepared by vertical twin roll casting in this paper. Since the absolute deformation during rolling was smaller,due to the small thickness of the strip of 3mm, the rolling of cast strip was different from the conventional rolling process. It was found that homogenizing time at 400°C for the cast strip was 4h and reduction per pass should be 8-10% for producing thinner (1-1.5mm) rolled AZ31 sheet at 350°C. Mechanical properties of the sheet were equivalent to conventional rolling sheet’s.

The magnesium alloys have poor corrosion resistance because of their low equilibrium potential and loose oxide film, while the aluminum and its alloys have good corrosion resistance due to their compact oxide film. In this study, a kind of aluminum and magnesium bimetallic bars, 6063 aluminum alloy-clad AZ31B magnesium alloy bars, were acquired through hot extrusion. The experimental results showed that the extrusion temperature of 653K or lower, as well as an extrusion speed of 2m/min or lower be used during the extrusion. The interfacial structure and mechanical properties of the bimetallic bars were studied. The interface between aluminum alloy and magnesium alloy was metallurgic bonding with the shear bonding strength of 53Mpa for as extruded sample. As annealing temperature or holding time increased, the jointed layer between aluminum alloy and magnesium alloy was broadened, which decreased of shear bonding strength, indicating that the heat treatment is deleterious. The bimetallic bars have lower identity, good corrosion resistance and preferable mechanical properties, which are promising constructional materials.

This study reports a novel method for the preparation of several biologically important calcium phosphate (Ca-P) phases such as hydroxyapatite (HA), dicalcium phosphate dihydrate (DCPD) and dicalcium phosphate anhydrous (DCPA). X-ray diffraction (XRD) results showed that phase pure DCPD, DCPA and HA nano-crystals could be produced in the Ca2+/PO4 3- solutions with the presence of EDTA at 120 oC, 180 oC and 210 oC, respectively. Transmission electron microscope (TEM) micrographs revealed that all the Ca-P precipitates were needle-like or rod-like. Most of the precipitates ranged from 100 ~ 200 nm in length. Selected area electron diffraction confirmed that the longitude direction of the rod-like HA precipitates were along c-axis and the flat surface was (110). Thermal gravimetric analysis of the DCPD precipitates revealed that phase transformations of DCPD to DCPA and DCPA to HA occurred at 139 oC and 195 oC, respectively, which resulted in the different Ca-P phases during hydrothermal synthesis at different temperature ranges.

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.

The dynamic recrystallization characteristic of 3104 alloy has been investigated by isothermal compression deformation at temperatures from 573K to 773K under constant strain rates ranges from 10-3s-1 to 1s-1. It was shown that the form of flow stress curves were very sensitive to temperature and strain rate. At high temperatures and low strain rates, dynamic recrystallization of 3104 alloy deformation occured. The critical value for dynamic recrystallization start was determined from an inflection point that was observed in the plot of work hardening rate vs. flow stress and verified metallograhically based on quenching samples interrupted during deformation. In the experimental domain studied, the ratio of the critical strain for the initiation of dynamic recrystallization to that of the peak strain falled in the range 0.4-0.6. Furthermore, the dependence of εc on Zener-Hollomon parameter( Z) has been developed.

The deformation behavior of AZ31 magnesium alloy has been investigated by isothermal compression at temperatures between 573-723K and at constant strain rates ranging from 10-3 -1s-1. It is shown that the form of flow stress curves is very sensitive to temperature and strain rate. In the experimental domain studied, the flow stresses are modeled using a power law with an average activation energy of 145.16 kJ/mol, and dynamic recrystallization (DRX) occurs. The critical strain for DRX is determined by analysis of flow stress curves. The ratio of the critical strain to the peak strain falls in the range of 0.4-0.5. At low temperatures and high strai rates, the deformation become macroscopically inhomogeneous, and the fracture of the specimens is accompanied by shear banding. Grain refinement resulting from DRX is less effective at high temperatures due to rapid grain growth. It is also shown that there is no difference between peak stress and stable state stress at high temperatures and lower strain rates, presenting the feature of continuous dynamic recrystallization (CDRX).

Conventional manufacturing processes of metal and alloys sheets are rolling. The poor formability of magnesium alloys at room temperature makes rolling difficult. In the present paper, a manufacturing technique of sheets by powder rolling was employed to fabricate magnesium alloy sheets. The technique consisted of roll compaction, sintering, re-rolling and annealing. Powders of Mg-3 wt% Al mixed using a global mill were roll compacted into green sheets using two counter rotating rolls to the thickness of approximately 0.60 mm. Roll compacted green sheets were sintered at 823 K in argon atmosphere. Sintered green sheets were then re-rolled at ambient temperature to approximately 0.22 mm to obtain fully dense sheets. There was no significant edge cracking observed in the process of cold rolling. It is reasonable to believe that powder rolling is a promising technique for manufacturing magnesium alloys sheets.

Particle-stimulated nucleation (PSN) was investigated in magnesium alloy AZ31 to study the effect of the evolution of second-phases during extrusion and other metal forming processes. Compression tests were carried out on samples taken from coarse-grained as-cast magnesium alloy billets containing a lamellar Mg17All2 eutectic phase and (Al, Mn) particles. These revealed that particle-stimulated DRX nucleation (PSN) was taking place during hot deformation and that this is facilitated by the fragmentation of the Mg17All2. When Mg17All2 dissolves into the matrix at about 350°C, the (Al, Mn) particles remain effective in producing PSN at temperatures up to at least 400°C. This suggests that alloy design leading to a suitable distribution of second-phase particles can improve the properties and formability of wrought magnesium alloys.

Blood content and tumor oxygen level are important biomarkers and prognostic indicators in patients with colorectal cancer (CRC). However, noninvasive measurements of both quantities in human colon are limited. In this study, we extracted the total hemoglobin concentration (THC) and oxygen saturation (StO(2)) of normal, premalignant, and malignant colonic tissues in 27 patients using a diffuse reflectance instrument and algorithms based on the diffusion equation. The mean+/-standard error of THC and StO(2) from all normal sites (n=26) is 93.4+/-17.1microM and 67.2+/-3.7%, respectively. THC increased to 136.9+/-23.8microM and 153.8+/-38.6microM and StO(2) decreased to 51.3+/-7.0% and 26.4+/-6.1% for premalignant and malignant tissues, respectively. The disease-to-normal THC ratios are 3.2+/-1.1 and 4.4+/-1.9 and the disease-to-normal StO(2) ratios are 0.7+/-0.1 and 0.5+/-0.1 for pr alignant and malignant tissues, respectively. These results demonstrate the feasibility of a robust optical method to assess colon THC and StO2 at all stages of carcinogenesis in vivo so that the angiogenesis and hypoxia of the disease and the therapeutic role can be studied in CRC patients.

In this paper we propose a new power-aware routing protocols TBPR (Time-based Broadcasting for Power-aware Routing) for wireless ad hoc network. Unlike conventional power-aware protocols, our protocol not only considers accumulated power consumption as a routing metric, but also utilizes a mechanism of controlling rebroadcasting route request packets to optimize the power conserving performance. Simulation results demonstrate that the proposed protocol outperforms other power-aware schemes: MCPR, MBCR and AODV.