Abstract: The microstructure and phase structure of AlCoCrTiNiCu_x which are made of six class transition metal elements have been studied in this paper. The results indicated that the change process of microcosmic crystal-structure of the five group high entropy alloy of AlCoCrTiNiCu_x system is transformed from FCC（mainly）+ BCC crystal structure (X=0.5、X=0.8) to FCC+BCC+ primary lattice crystal structure (X=1.0、X=1.2), finally, the crystal-structure turn into BCC+ primary lattice crystal structure as the content of Cu further increasing.
Abstract: Research the electrical conductivity, tensile strength, elongation and microstructure of Cu-2.3Ni-0.24Si alloy in as-cast, hot rolled plate, solution treatment plate, cold rolled strip, and aging treatment strip. the results show that hot rolled at 870°C×1h, solution treatment at 850°C×1h, following 87% cold-rolled, and than aging treatment at 450°C×1h, the tensile strength, elongation and electrical conductivity are 519MPa, 8%, and 45% IACS respectively.
Abstract: Simulation software is an essential tool for today‘s engineers. Its application enables castings to be designed with predicting the final results prior to they are produced. Thus, the simulation plays significant role in casting production. If a realistic calculation of the mold filling and solidification processes can be made it is possible to predict casting defects caused by casting system and/or casting design. In order to understand the changes occurring during solidification of casting, numerical simulation has been used in our classroom teachings for postgraduates. The software structures, mathematical principles, software utility, functions and output criteria are introduced in this paper to demonstrate that computer aided instruction is of Intuitive, attractive and can be used in classroom before the real experiments as assistant means to help postgraduates to understand what is casting and what is solidification
Abstract: The precipitation hardening response of as-cast Mg-8Yb-0.5Zr magnesium alloy was investigated in the present work. The microstructure evolution of the alloy illustrated that Mg2Yb intermetallic phase was dissolved by solution heat treatment at 520°C for 12 hours. An apparent precipitation hardening response in Mg-8Yb-0.5Zr was discovered after artificial aging at 150°C, with maximum hardness increment of about 80 percent at the peak condition. It was found that the precipitates of the alloy were in the shape of two conjoined cosh and globe about 50 nm, and precipitated preferentially on grain boundaries and dislocations.
Abstract: A mesoscopic crystalline model was proposed to quantitatively analyze the relative activities of deformation modes involved in the plastic deformation of an AZ31 magnesium alloy at room temperature. The plastic response of a cast AZ31 magnesium alloy with random texture can be well predicted by this model. It is demonstrated that the remarkable difference of relative activities of pyramidal slip should be attributed to the different strain hardening behavior in tension and compression. Further TEM micrographs shows the occurrence of pyramidal slip in compression, which confirms the validity of the proposed model.
Abstract: Magnesium alloy of 6% Ca and 9% Ca, produced by spray deposited method, was heat treated at different solid-solution and the same aging treatment. The microstructure and hardness were analyzed by SEM, XRD and HV tester. The experimental results showed that Ca can make the spray deposited magnesium matrix grains refine uniformly, the second phase particle Al2Ca and CaZn are formed and the hardness value increase. With the rise of solution temperature, the hardness of 6%Ca and 9%Ca magnesium alloy rise firstly and then fall, and the hardness value of 6%Ca increase to the highest 121Hv and 9%Ca increase to the highest 128Hv after 370°C/3h+205°C/24h.
Abstract: Zirconium rich corner’s isothermal section of the Zr-Sn-Nb system at 450°C was determined by using X-ray diffraction. Experiment results showed that this isothermal section consisted of 2 three-phase region: ((βNb) + Zr4Sn + (αZr)) and (Zr4Sn + (βNb) + Zr5Sn3), 3 two-phases region: ((βNb) + (αZr)), (Zr4Sn + Zr5Sn3) and (Zr4Sn + (αZr)), and 4 single-phase region: (βNb), (αZr), Zr4Sn, Zr5Sn3.
Abstract: Passivator components of phytic acid, hydrogen peroxide, boric acid and polyethylene glycol was optimized by orthogonal experiment. Corrosion resistance of passivation film of brass-strip was invertigated by salt spraying, weight loss and electrochemical test. The results show that the optimization passivator consists of phytic acid (50% mass fraction) 8ml/L, hydrogen peroxide (mass fraction 30%) 30ml/L, boric acid 5g/L, polyethylene glycol 15ml/L and additive 4g/L. Corrosion current density and corrosion rate of the brass-strip specimens coated by rich-phytic acid passivator are similar to that treated by traditional sodium dichromate passivator, the characteristic of anti-tarnish slightly better than that coated by sodium dichromate passivator. The feature of rich-phytic acid passivator is environmental protection.
Abstract: In this paper, a AlMgSi alloy for sheet materials was designed on the base of 6111 aluminum alloy, the alloy sheet was fabricated by the rolling process combination of hot and cold rolling, the effect of rolling process on the microstructure of alloy was studied. The results show that different 1st rolling pass reductions of 13%, 33% and 47%, alloy microstructure changes obviously. With the increasing of 1st rolling pass reductions, the re-crystallization structure grow in quantity, re-crystallization grain more and more dense, flat, uniform, and the second phase particles are also more small, distributes more uniform. When the first cold rolled reduction is 47%, degree of grain refinement, the second phase particles fragmentation and tissue uniformity in rolling 3st state are obviously superior to the 1st state and 2st states. The deformation inhomogeneity can be overcome by improving the first reduction rate, the re-crystallization process of synchronization between surface layer and the center layer is better.