Advanced Materials Research Vols. 189-193

Abstract: Samples of mineral-like materials based perovskite and model high-level wastes (strontium) were fabricated by the SHS-densification and tested. The results of MCC-1, XRD and SEM/EDS analysis show that the major phase is well concordant with the design. The samples were characterized by dense structure and fine chemical stability. It is a durable material with high-level waste loading and is in favor for final geological disposal.

Abstract: Mg-6Li-3Zn alloy sheets were prepared by melting and casting, and heavy rolling with a total reduction of 94%. The high-temperature mechanical behavior, microstructures and deformation mechanisms were investigated. The maximum elongation to failure of 300% was demonstrated at 623K and an initial strain rate of 1.67×10^-3s^-1. Observations by optical microscope, transmission electron microscope reveal that significant dynamic recrystallization and grain refinement occurred in banded grains at 573K and an initial strain rate of 1.67×10^-3s^-1, under which the subgrain contour was ambiguous and dislocation distribution was relatively uniform. It is shown by newly constructed deformation mechanism map that the high-temperature deformation mechanism in Mg-6Li-3Zn alloy sheet with banded grains at 573K and an initial strain rate of 1.67×10^-3 s^-1 is dislocation viscous glide controlled by lattice diffusion, the stress exponent is 3 (strain rate sensitivity exponent 0.33) and deformation activation energy is 134.8 kJ mol^-1, which is the same as the lattice diffusion activation energy of magnesium.

Abstract: The shape of rod-shaped parts is complex, and the relative size changes more, so it is difficult to be deformed. Naturally the production of rod by closed multi-ram forging has many advantages. This paper introduces the analysis and calculation of the deformation load in auto rod pieces by closed multi-ram forging and the solve process of formula calculating deformation load of multi-ram forging, and then verified it by experiment. It has been shown that upper-bound analysis method is accurate in calculating the deformation load of multi-ram forging, and it can be used as the basis of the selection of presses and calculating the deformation load.

Abstract: Based on the new generation TMCP technology, The State Key Laboratory of rolling and automation, Northeastern University(RAL) developed an advanced cooling system(ADCOS-PM). The system was combination of ultra-fast cooling (UFC) equipment with the advantage of high cooling intensity and homogeneous cooling and traditional accelerated cooling equipment(ACC). The UFC equipment was composed of jet impingement cooling device with high-pressure water and the ACC equipment was composed of laminar cooling device with good controllability. The control object of ADCOS-PM control system including finish cooling temperature and cooling-rate of every stage was controlled by adjusting the parameters such as the run-out table speed, state of active and inactive jet, flow rate of active jet. The temperature profile of plate was completed on the run-out table so that the product with fine microstructure and good mechanical properties was produced. The ADCOS-PM was built in 4300mm plate mill of Anshan Iron and Steel Co., Ltd. in 2010 and the recycling products with high-performance were produced.

Abstract: Process simulation is a powerful tool to predict material behaviors under specified deformation conditions, so as to optimize the processing parameters. The equation for flow stress is important to numerically analyze. However, the reported constitutive equations of magnesium alloy are only suitable for processing simulation with strain rate between 0.001-1s-1. In this paper, the strain-stress behavior of AZ31 under warm and high strain rate (>103s-1) condition has been investigated by split Hopkinson pressure bar experiments at elevated temperature. The results show that the influence of the temperature on flow stress is more obvious than that of strain rate; the flow stress decreases with the rise of temperature at a certain strain rate. Based on Johnson-Cook model, the constitutive equation of AZ31 magnesium alloy under warm and high strain rate condition has been given out by fitting the experimental data, which can be applied in process simulation of AZ31 magnesium alloy sheet forming.

Abstract: The paper introduces injection mould 3D parts library parametric reusable technology development which is on the basis of UG. The built 3D parts library injection mould which uses VisualC + + 6.0 and UG/Open secondary developing tools can realize the injection mould parts of model parameter driving and reusable functionality. It can make mould designer directly call besides cores outside of the parts, improve the efficiency of the mould design and effectively shorten the development cycle of mould.

Abstract: To study the maintenance resources deployment optimization, the resource usage characteristic was analyzed and a maintenance process model was constructed considering multi-team sharing test equipment. Applying model, the quantitative analysis was made and the maintenance performance of different resources deployment was provided.

Abstract: The thixo-forging of magnesium matrix composite was analyzed with computer numerical simulation based on rigid viscoplastic finite element method. The constitutive model of SiCp/AZ61 composite was established in our prior literature. Behavior of metal flow and temperature field were obtained. The differences between traditional forging and thixo-forging processes were analyzed. Results indicated that thixo-forging was better in filling cavity than forging. Simulation results were good agreement with experimental ones.

Abstract: The limit drawing ratios of the steel sheets are studied by the numerical simulation using the finite element software PAM-STAMP 2G. The limit drawing ratios of the steel sheets are also measured by the practical Swift cup test. The results of the experiments and the simulations are compared and analyzed. The results show that the overall shapes of the deep drawing parts of the experiment and the simulation are roughly the same. The maximum deviation of limit drawing ratio values between the experimental results and the simulations for two steel sheets with various thicknesses is only 2.2%. The deviation of limit drawing ratio of steel sheet obtained through PAM-STAMP FEM software is small. The PAM-STAMP software is highly reliable for the steel sheet deep drawing simulation.

Abstract: This paper briefly introduced the principle of Rapid Heat Cycle Molding. Researches and applications of Rapid Heat Cycle Molding were reviewed, and heating method and mold structure were emphatically studied. At last the exiting problems and trend were proposed.