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Composite mold samples used in squeeze casting was fabricated by plasma spraying with 5CrMnMo and 3YSZ, which was shown high bonding strength and good thermal shock resistance. The best parameters with transition coat were explored by mechanical analyses. As results, the transition layer structure made of 75 percent NiCoCrAlY powders showed bonding strength was higher to 34.35MPa and that thermal cycles were up to 46.8 times. The effect of the transition layer was analyzed by microstructures and the failure mechanism of the coating material with a transition layer was discussed. The conclusion was that the physical mismatch and thermodynamic mismatch between the matrix and ceramic layers were the main cause of the failure.

Herein, warm drawing technology assisted by an electric current heating system is proposed to minimize the formation of wrinkles and cracks on the surface of Q390A high-strength steel V-shaped stiffeners during cold forming. V-shaped stiffeners with excellent properties were obtained by elevating the forming temperature and improving the material plasticity. The influence of temperature and tensile rate on the mechanical properties of the Q390A high-strength steel at 400-800°C was investigated. The effects of blankholder force and friction coefficient on the formed parts were simulated and analyzed by the finite element simulation software DYNAFORM. The law of heating and cooling for the formed parts during the forming process was studied through the electric current heating experiments. The forming temperature was controlled from 530 to 720 °C as the current density was maintained in the range from 7.3 to 8.5 A/mm2. Surface oxidation, cracks, sheet warping degree, sectional thickness distribution, mechanical properties, and microstructure of the V-shaped stiffeners formed at 400 to 700 °C were analyzed. The results show that the V-shaped stiffeners formed at 600 °C possess excellent overall properties.

In order to meet the high mobility and lightweight requirements of tracked special vehicles, a novel dual-grouser track shoe component was designed and formed by forging. The thickness of thinnest connection area between two grousers was only 3mm. The low-alloy wear-resisting steel 42CrMo was chosen as the raw material, which enables to solve the drawbacks of non-ferrous metal under the low-intensity-impacting condition. The stress-strain fields of the part during forming were simulated and analyzed using the Finite Element (FE) simulation software, Deform-3D. In addition, the microstructure and mechanical properties of the formed parts demonstrated that the forging process could exhibit a good forming effect with precise dimension and stable quality accomplished. The yield strength, ultimate tensile strength and fracture elongation of the connection area between two grousers were 788MPa, 467MPa and 19.5%. Furthermore, the wear rate and coefficient of friction of this area were 0.015mg/(km·N) and 0.37. Such kind of novel 42CrMo dual-grouser track shoe component is able to offer a lower production costs and longer service duration.

The effects of a variable-cavity liquid forging process on the microstructure and mechanical properties of an Mg-5Zn-1Y-0.6Zr magnesium alloy are described based on the results and analysis. The results indicate that the microstructure of the alloy changed clearly during the deformation process. After variable-cavity liquid forging, the dendrites are elongated along the deformation direction. The alloys with different deformation temperatures consist of α-Mg, the Mg-Zn phase, the I-phase (Mg3YZn6) and the W-phase (Mg3Y2Zn3). The I- and W-phases are mainly distributed in the grain boundaries, and the Mg-Zn phase is mainly dispersed in the grains. Most of second phase is broken into fine particles during the variable-cavity forging process. There is high dislocation density in the elongated grains at a deformation temperature of 350 °C, especially near the grain boundaries. Due to the dislocations, there are some tiny subgrain structures (less than 1 μm) formed near the second phase. After the variable-cavity liquid forging process, the subgrain structures did not recrystallize. The mechanical properties are significantly affected by the second phase and size of the grains. The highest tensile strength is 351.5 MPa at a deformation temperature of 350 °C, which is due to retained eutectic pockets. The best elongation is 7.15% at a deformation temperature of 450 °C, which is due to the tiny second phase particles and fine grains.

In this work, 7075 Al alloy, a high-strength wrought aluminum alloy with high hot tearing sensibility, was used in the squeeze casting of an asymmetric part. The solidification defects, microstructures and mechanical properties of the part solidified under different forming pressures were studied. Furthermore, the uniformities of the microstructures, mechanical properties and the solidification mechanisms were investigated. Results show that increasing the forming pressure is helpful to improve the liquid/solid feeding for counteracting the particularly serious shrinkage during the wide mushy zone of 7075 Al alloy. Therefore, the solidification defect can be avoided. Moreover, increasing the forming pressure is helpful to not only obtaining fine equiaxed grains, but also diminishing the intergranular segregation of alloying elements. With the increasement of forming pressures, the strengths of the part increased, along with the decreases in the ductile due to the work hardening resulted from the serious solid feeding. The microstructures and mechanical properties are impacted by the solidification rate of the melt at different regions. When the forming pressure was 150 MPa, fine microstructures and excellent mechanical properties were obtained. The uniformity of the microstructures and mechanical properties are dominated by the solidification location sequence of the melt. Further on, it is determined by the thermal gradient of the melt at different locations. For 7xxx series alloys, more solid feeding is needed for counteracting the serious shrinkage at the first solidified regions, causing a work hardening and associated strengths increasements. A near uniform part thickness and direct feeding loads are appreciated to improve the uniformities. In this work, the optimal tensile properties tested in the part were tested to be as follows: the yield strength (YS), ultimate tensile strength (UTS), and elongation (EL) are 345.5 MPa, 483.2 MPa, and 7.6%, respectively. The UTS uniformity is tested to be 86.4%.

The development of electric vehicle batteries has resulted in high energy density battery pack. Cell-to-Pack (CTP) omits the cell module assembly, can reduce battery pack parts by 40%, improve the battery pack volume utilization rate by 15%–20%. However, the thermal characteristics of CTP under full operating conditions has yet to be verified, the CTP temperature calibration cycle under full working condition is time-consuming, and little analysis has been conducted on CTP internal temperature differentials and heat flow. The present study aims to thermal characteristics of CTP. Results show that CTP temperature calibration based on a thermal resistance grid can realize internal temperature reconstruction, optimum temperature arrangement, and shorten the calibration period by more than 60%. In addition, higher ambient temperatures can increase the maximum temperature of the jelly rolls in CTP cells, while lower ambient temperature can lead to larger differences in jelly roll temperature within a cell; and high-speed driving and fast charging can lead to the highest temperature increase rates under different working conditions up to 0.05 °C s−1.70% of the heat generated during cell discharge is used for self-heating, and the heat dissipation of liquid cooled plate is the main heat dissipation channel.

Cold is an important cause of the death of people who fall into the water. The use of a gas generating agent to inflate an inflatable lifejacket is a kind of self-heating inflatable lifejacket, which maintains the inflation effect and portability of the original lifejacket and can also play an auxiliary heating effect. In this paper, a nitrogen-rich substance, 5-aminotetrazole 3-nitro-1,2,4-triazole (5ATNTZ) was synthesized, together with the selected oxidant and binder to complete the preparation of the gas generating agent. Commercial life jackets were selected for inflation test to explore the actual dosage and inflation effect of gas generating agent. The experimental results show that when the amount of gas generating agent is 19 g, the amount of physical coolant is 20 g, and the amount of chemical coolant is 7 g, the lifejacket is inflated and its surface temperature reaches at least 40.3 °C. The energy utilization efficiency reaches 75.17% when the chemical energy of the gas generating agent is converted into the heat of the bag and inflation work in the whole inflation process. Therefore, the gas-filled lifejacket using a gas generating agent has a good auxiliary heat effect, and is a type of self-heating inflatable lifejacket with excellent performance, which has great application value.

Mg-Zn-Zr-Y billets with different mass fraction of Y (wt%(Y)=0.2%、0.5%、1.0%、1.5%、2.0%) was prepared by permanent mold casting. The increase in Y content has shown grain refinement effects on the microstructure morphologies of Mg–Zn–Y–Zr alloys. When the content of Y achieves 1.0 wt%, the grain refinement effect of the Y is most obvious than any more contents of the Y content. In the test result of XRD, the type of precipitated phase in Mg-Zn-Zr-Y alloys is related to atomic ratio of Y/Zn. With content of Y increases, atomic ratio of Y/Zn increases,the precipitated phase in alloy is changed from Phase I to Phase W. Tensile strength and extension rate of alloy increase with the increasing of Y content; When Y content reaches 1.0%, mechanical property reaches maximum value.When content of Y exceeds 1.0%, with the increasing of Y content, mechanical property of alloy declines gradually.

In order to study the thermal safety of cylindrical battery deeply, based on the theory of heat transfer, thermal explosion and nonlinear modeling, a three-dimensional non-steady state thermal explosion mathematical model of cylindrical fireworks with non-uniform heat dissipation of the lateral surface was established for the first time (three-dimensional partial differential equation group). Combining seven point difference method and Newton-homotopy algorithm, the numerical calculation method of the three-dimensional non-steady state thermal explosion partial differential equation was established and the numerical calculation program was written base on Matlab. The validity of calculation program has been demonstrated by comparison of numerical solutions and classical solutions. The accuracy of model has been validated by example computation and analysis. The critical parameters describing non-steady state model of cylindrical fireworks when stored individually and stored in combination form were calculated in this paper, including temperature distribution, temperature–time history, thermal explosion time to ignition, etc. The results show that when the ambient temperature is 450 K, the fireworks stored individually do not have thermal explosion, but the fireworks stored in combination form will explode finally and the thermal explosion time to ignition is 19013.53 s. When the ambient temperature is 460 K, thermal explosion will occur in both the fireworks stored individually and stored in combination form, and the thermal explosion time to ignition are 3187.07 s and 3066.60 s respectively. It shows a more exact analytical methods and solutions of thermal safety evaluation of fireworks was established in this paper. Thus, it is need to strengthen the safety monitoring and management of cylindrical battery (combined fireworks) because of the higher thermal hazard.

The formation process of Al3Ti was studied based on the in-situ reaction between globular solid Ti powders with almost uniform size and 2024 Al melt under ultrasonic vibration. The microstructures of the Al3Ti/Al composite were examined at different reaction time. The reaction mechanism was analyzed based on the phase diagram and empirical reaction kinetics. Moreover, the effects of ultrasonic vibration on the formation of Al3Ti were discussed. The results show that the Al3Ti formed a layer around the unreacted Ti particle and was ruptured as the reaction continuing. An empirical reaction kinetics model of in-situ Al3Ti was established. The kinetic exponent n is determined to be 0.86, which is much higher than that of the standard diffusion-controlled growth (n = 0.5). The ultrasound assisted reaction follows an interface-controlled growth which means a higher reaction rate. The comprehensive effects of instantaneous pressure, high-intensity shock waves and local high-temperature caused by acoustic streaming and cavitation, are responsible for the high reaction rate and fine Al3Ti particles during the reaction process under ultrasonic vibration.

Taking carbon series conductive coatings as the research object, research on a modificatory filler was carried out to achieve higher electrical conductivity. Under the condition of this paper, the conductivity of the modified carbon black was improved, while the performance of the modified graphite was not obviously improved. The conductivity and dispersion of the modified carbon fibre were both improved. Analysing the impact of the additive on the performance of conductive coatings in which carbon black accounted for 10%, the conductivity was best when the weight of the tetra-butyl titanate was 1% of the filler. Adding an anti-settlement agent also improved the performance of the conductive coatings, and the best consumption was about 0.6% of the weight of the filler.

Ag/TiO 2 anodes treated with TiCl 4 were prepared by sol and powder combination technology. Scanning electron microscope (SEM) shows that Ag/TiO 2 film is denser and has fewer gaps after TiCl 4 treatment. X-ray diffraction (XRD) indicates that the TiCl 4 treatment can significantly make the TiO 2 particle size become smaller on the electrode surface. Diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy associated with NH 3 adsorption confirms that the amount of anode surface acidity increase after TiCl 4 treatment. Electrochemical impedance spectroscopy (EIS) measurements show that the R ct2 corresponding to the TiO 2 /dye/electrolyte interface decrease to 3.5 Ω. The TiCl 4 treatment can provide more specific binding sites to the alkaline dyes. Much more dyes can be adsorbed. Therefore, the photoelectric conversion efficiency of dye-sensitized solar cell (DSSC) was improved.

The high strength 7xxx series aluminium alloys are usually difficult to be prepared as semi-solid feedstock, because some dispersoid particles (soluble only in liquid) could pin at grain and subgrain boundary to make the alloy difficultly recrystallise. In this work, a novel multistep reheating regime is developed for recrystallisation and partial melting (RAP) route to prepare fine spheroidal microstructure of semi-solid Al–Zn–Mg–Cu alloy. After reheating to 665 °C, holding for 4 min and subsequent isothermally holding at 620 °C with total heating time of 15 min, fine spheroidal microstructures with grain size of ∼40 μm were prepared without remained unrecrystallised grains and directionality, which are much finer than the conventionally obtained microstructures (∼100 μm).

A set of novel forming die combining the advantages of dies casting and forging was designed, by which double control forming idea was firstly proposed. The motorcycle wheel made of AM60B alloy was used as the typical component to demonstrate advantages of the double control forming. The effect of pressure on the mechanical properties and microstructure of the parts formed by double control forming was investigated. The results showed that high mechanical properties and complex shape were achieved in the parts formed by double control forming. Compared to die casting, the mechanical properties of the formed part significantly increased and the microstructure changed from the coarse dendrites to fine equiaxed grains. The shrinkage voids and microcracks in the formed parts were obviously reduced or even completely eliminated with the increase of pressure. When a pressure of 4000 kN was applied, the optimal mechanical properties such as ultimate tensile strength of 265.6 MPa and elongation of 21% were achieved and the microstructure was characterized by fine and uniform equiaxed grains due to the large undercooling degree caused by the high pressure.

Thin-wall and high-rib components of AM60B Mg alloy were formed by double control forming (DCF) under the optimal conditions. Numerical simulation of high-speed filling process was carried out on Flow-3D software. The microstructure and properties of the components formed by DCF under the optimal conditions were investigated. The results showed that the design of the overflow launders and runners were feasible. The velocity magnitude in the component region was less than that in the regions of the runners and overflow launders. The temperature decreased gradually from the runners to overflow launders. Finer and more uniform microstructure without defects such as microcrack and microporosity was found in the components formed by DCF as compared to die casting. The reason was due to the dual effect of high pressure on increasing the nucleation rate and removing the defects. The mechanical properties of the components formed by DCF under the optimal conditions were significantly improved in comparison to die casting and DCF under non-optimal conditions. Fine and uniform microstructure without defects led to the improvement of mechanical properties. The fracture morphology of the components formed by die casting was characterized by brittle cleavage fracture and some microporosities, deteriorating the mechanical properties. Ductile fracture morphology with a large number of dimples was found in the fracture microstructure of the components formed by DCF under the optimal conditions, enhancing the mechanical properties.

An easy method to synthesize hollow carbon nanospheres (HCSs) with polystyrene as template and phenol as precursor is reported. The obtained HCSs have very thin shells and big hollow cores. The diffraction peaks of X-ray diffraction patterns located at about 2 θ = 22° and 43° are assigned to the (0 0 2) and (1 1 0) graphite plane of HCSs. Transmission electron microscopy shows every state in the synthesis process of HCSs.