Advanced Materials Research Vols. 189-193

Abstract: Analysis the electricmotorcar aluminum wheels’ hole defect on macroscopic and microscopic, observed that the main defects、concentrated site and the main alloy phase. Combined with the local casting technological parameters, the filling and solidification process of aluminium alloy hub was simulated by using Anycasting software. The results showed that: castings filling smoothly, at the junction of the spoke and the rim and the hub central are easy to produce casting defects. Using the optimized process parameters that is lower pouring temperature, higher pouring height and set the vent to experiment, after comparing the results with the original process known, Shrinkage and porosity defects decreased, but there are still some degree of defects, indicating optimized process parameters have some effect.

Abstract: The Dendrite Coherency Point (DCP) of A357 alloy was determined after different melt treatments by double thermocouples, and the coherency solid fraction (fscoh) was calculated by thermal analysis. The results of dendrite coherency properties show that fscoh values increase with increased cooling rate for A357 alloy. For A357 alloys, fscoh values increase after grain refined and melt superheat treatment. The coherency point was found to be dependent on not only the morphology of the dendrites but also the dendrite growth rate.

Abstract: The casting Fe₃Al intermetallics were solidified in sodium silicate sand mould and permanent mould respectively to get different cooling rates. After heat treatment (1000°С/15 h homogenizing annealing + furnace cooling followed by 600°С/1 h tempering + oil quenching), the microstructure and properties of Fe₃Al intermetallics were investigated. The results show that the heat-treated Fe₃Al intermetallics at higher cooling rate has finer grained microstructure than lower cooling rate, and the lattice distortion increases due to the higher solid solubility of the elements Cr and B at higher cooling rate. The tensile strength and hardness of the Fe₃Al intermetallics at higher cooling rate are slightly higher also. However, the impact power of intermetallics at higher cooling rate is 67.5% higher than that at lower cooling rate, and the impact fracture mode is also transformed from intercrystalline fracture at lower cooling rate to intercrystallin+transcrystalline mixed fracture at higher cooling rate.

Abstract: Electro-slag remelting (ESR) is a kind of special metallurgy techniques to produce high quality alloy materials. The interface of electrode and slag is the energy entrance of entire system in the remelting process. Mathematical model of consumable electrode’s melting process has been built in this paper. Some valuable variation rules of droplet diameter, droplet forming time, melting rate and purification coefficient following melting current and slag bath depth have been studied through a series of simulation work. Based on the mechanism studying of the consumable electrode’s melting, some meaningful experience to optimize the technological parameters and improve material quality of electro slag ingot has been gotten.

Abstract: In view of the process of flowing steel before the establishment of strip casting, the low superheat forced pouring continuous casting technology, i.e. the molten steel is cooled by the rotating cooling rollers, then it is forced to flow into mold, has been put forward in order to reduce superheat of liquid steel, enhance the efficiency of heat transfer and improve inner structure of billet. The filling and solidification processes of low superheat casting and submerged entry nozzle(SEN) casting are numerical simulated using fluid dynamics software. It is gained that velocity distributing diagrams, temperature distributing diagrams and solidification distribution diagrams at different time in the filling process. Influences of twin-roller cooling pouring on velocity field, temperature field and solidification are analyzed. The results show that the superheat of liquid steel is decreased and the solidification rate of liquid steel is increased by low superheat casting of twin-roller cooling process, which is favorable to improving the quality of billet and enhancing pull speed.

Abstract: Ultrasonic Wave was used to assist alkali extraction and acid precipitation of peanut protein isolate from defatted peanut powder. Based on the single factor test, the response surface analysis results shows that the Ultrasonic Wave-assisted Extraction condition is: ultrasonic power 210W, ultrasonic time 30min, ultrasonic temperature 40°C ,solid to liquid ratio 1:10.7, and under this improved condition the extraction yield could reach 80.09%.

Abstract: Properly annealed Ti₅₀Ni₂₅Cu₂₅ amorphous ribbons have excellent shape memory founction, superelastic and internal friction. In this article, recent progress in research on the amorphous alloy ribbons of Ti₅₀Ni₂₅Cu₂₅ preparation method, phase composition, microstructure of the research status were reviewed. The review mainly includes the phase composition, microstructure evolution, supporting the process of structure change and phase change after heat treatment on Ti₅₀Ni₂₅Cu₂₅ crystallized amorphous ribbons.Shortcomings and future researching fields were also pointed out.

Abstract: Technological process of microwave-assisted leaching of vanadium with sulfate solution has been defined on the base of phase and chemical constituents of stone coal. The influence factors such as content of sulfuric acid, microwave power, and leaching time were studied on leaching rate of vanadium from the stone coal. One element experiments and orthogonal design experiments are carried out to achieve optimized parameters. The experimental results showed that the leaching rate of vanadium was improved by the change of influence factors at some range. The single leaching rate of vanadium reached 80.9% under the optimal conditions of sulfuric acid content of 12%, microwave power 539w,leaching time of 2h.

Abstract: The effects of cooling condition on the Zr-rich core formation and grain size in Mg-Zr alloys were investigated in this study. Four moulds with various cooling rates and different Zr additions were used. The results show that when Zr addition was 1.2%, the Zr-rich cores were round and their diameters increased with decreased cooling rates. When Zr addition content was decreased to 0.7%, Zr-rich cores formed only in the sand mould with the lowest cooling rate used in this study, and the morphology changed to rosette-like. The influence of cooling rate on grain size of Mg-Zr alloys was also investigated.

Abstract: Suaeda salsa oil was taken as raw materials to produce biodiesel by ultrasonic-Assisted transesterification. Single factor experiment and the orthogonal experiment combination design were adopted to study the effects of ultrasonic frequency, ultrasonic power，reaction temperature ，reaction time，catalyst dosage and mole ratio of methanol to oil on biodiesel production rate. The order of factors that influence the biodiesel production rate within the experimental range was as follows: catalyst dosage＞reaction time＞reaction temperature＞mole ratio of methanol to oil. The optimal technological parameters should be as follows: ultrasonic frequency 28kHz, ultrasonic power 210W, reaction temperature 65 , reaction time 10min,catalyst dosage 0.3%and mole ratio of methanol to oil 6, and biodiesel production rate is 97.93% under such conditions.