Advanced Materials Research Vols. 634-638

Abstract: Through composition designing, smelting, TMCP and normalizing on EH40 in laboratory, then mechanical properties are detected respectively in tensile and impact test, the results are dawn as follow. The yield strength, tensile strength, reduction of area, percentage elongation and impact toughness of EH40 samples, which are not normalized, reach the national standards. Yield strength and tensile strength of the normalizing samples are lower than the national standards, but the impact toughness decreases greatly. The research on EH40 reaches its goals, but the normalization process needs improvement in this test.

Abstract: Four kinds of fermi energy of lead anode plate were calculated by using first-principles. Different metals and different alloy elements of the fermi energy level were compared, the minimum electrode potential lead base alloy anode materials is known. The results calculations show that the adding alloy elements can reduce the electrode potential of the lead anode plate, four kinds of alloy systems Pb-Ag, Pb-Sb, Pb-Sr, Pb-Sn were calculated, the highest of fermi energy was Pb-Sb alloy. So the Pb-Sb alloy is expected to become the electrode potential minimum lead base alloy anode materials.

Abstract: PM Superalloy FGH96 is usually used as turbine disc materials. It is a kind of alloy with high purity, which has strict demands of the content of impurity elements, especially the element of sulphur. Because sulphur is accumulated in the grain boundary of manganese or iron, with the form of sulfide, it has great impact on the performance of PM Superalloy FGH96, such as toughness and fatigue property. Therefore, it is an important part of quantity control to detect accurately of the content of ultra-low sulphur in PM Superalloy FGH96. As the market demand of PM Superalloy FGH96 and quality becomes varied, it is a trend that PM Superalloy FGH96 has ultra-low content of sulphur (S: 0.0001%-0.0020%). Hence, the related analysis techniques are needed. A new method of analyzing Ultra-low Sulphur (S: 0.0001%-0.0020%) in PM Superalloy FGH96 is established in the article by selective experiments with relevant test conditions, such as combustion conditions and blank test, using infrared carbon-sulphur detector.

Abstract: To develop proper Ni-based alloys for high-temperature vitriol pump which is submitted the corrosion of vitriol and rush of liquid with solid particles, the equilibrium phase diagrams of some Ni-Cr-Fe-C-Mo-Si-Cu alloys were calculated by software Thermo-Calc. Based on the simulation results and the mechanism of sigma phase precipitation strengthening, the chemical composition of a new Ni-based alloy was proposed. The alloy was casted and treated by solid solution at 1373K+2h, followed cooling to 1323K and quenching in water at room temperature, then strengthened by ageing respectively at 973K, 1023K, 1073K, 1123K for 4h. It was investigated the phases by XRD, the microstructures by OM and SEM. The proposed alloy consists of g, s and M23C6 from 1073K to 1273K. The most amount of s phase is up to 12.45 % (mass) at 1023K, it decreases with the augment of equilibrium temperature. s phase disappears above 1323K. The amount of s phase is enough in alloy to supply good precipitation hardening at a large temperature range. Experimental results were compared with the results of phase diagram simulation by Thermo-Calc. The alloy can be effectively strengthened by sigma phase precipitation at the temperature from 1023K to 1073K. Experimental results verified the validity of phase diagram simulation.

Abstract: The energetic and electronic structure of α-type Ti_1-xX_x (X=Al and Zr, x=0.0625, 0.125, 0.185, 0.250, 0.3125and 0.375) binary alloys were calculated by the method of supercell and augmented plane waves plus local orbitals within generalized gradient approximation. The results show that the formation energy decreases with the composition of Al, while increases with composition of Zr, which indicate that α phase can be enhanced by increasing the Al contents while weaken by increasing Zr contents. The DOS results shows that the Fermi levels of Ti_1-x Al _x and Ti _1-x Zr _x fall on a dip of a DOS curve, which means the α structure of these alloys is stable. When the Al content is increased, the charge transfer between the Al and its neighbors becomes more evident, and enhance the stability of the α phase. With an increase of Zr content, repulsive interaction between two Ti atoms strengthen, which result in the α phase stability decrease.

Abstract: Macromolecule modification activator was prepared using prepolymer of HTBN end capped by HDI biuret (N-75). Then the ABS/PA6 co-blend polymer was prepared by anionic polymerization with putting ABS resin into molten caprolactam monomer at the temperature of 160°C~180°C and the sodium hydroxide being used as activator. In the system of in-situ synthetic ABS modified nylon resin ,when the content of ABS is at 10% with rubber modifier as compatiblizing agent for ABS and nylon, the impact strength of matrices stepped up obviously, and the effect is better than that in the system of rubber modification. Along with added ABS, the tensile strength and bending strength fell that is lower than the tensile strength of pure nylon but apparently higher than that of the rubber modification system. The increase usage of compatiblizing agent improved the intensity and rupture elongation of matrices. It was indicated that ABS obstructed spherulitic growth and resulted in the reduction of nylon crystallinity.

Abstract: Molecular dynamics (MD) simulations was used to investigate the structures and evolution of atom clusters in liquid Al-Pb alloys. Pair correlation functions and chemical short-rang-order (CSRO) parameters indicate that inhomogeneous atoms are prone to be repulsed while Al-Al and Pb-Pb clusters are easy to emerge. The Voronoi analysis shows that the main coordination number around Al atoms and polyhedron index vary with Pb increasing. The main coordination number abruptly decrease from 11 to 9 when the Pb atomic percentage range from 30% - 40% , proving that Al-Al and Pb-Pb clusters are prone to be separated.

Abstract: The solid-state diffusion bonding processes were successfully carried out to join new Ni-Cr-W superalloys at different temperatures (850°C-950°C), under pressures of 20MPa and holding 45min in a vacuum furnace by taking Cu foil as interlayer. The influence of bonding temperature on the microstructural evolution and the diffusion behavior across the joints was investigated in details. Results indicate that the Ni-Cu solid solutions in the interface lead to a sound bonding interface without any void or impurity. As the temperature increases, the reaction layers become thicker due to the decrease of M23C6 precipitation in the grain boundaries and the rise of atoms diffusion capability. Furthermore, hardness measuremental result also reveals that the increased thickness of reaction layers cannot improve the microhardness of bonding interfaces apparently.

Abstract: The objective of the study is separating the gold (I) and its coexistence base metals from cyanide leaching solution by homemade weak and strong alkaline anion exchange fiber inseries, by using their selectivity and the adsorption capacity, respectively. The optimal conditions of the adsorption/elution are as follows: for WAAEF, the suitable flow rate of the adsorption is 61.4 BV/h, and the loading density is 0.262 g/cm3; for SAAEF, the suitable flow rate of the adsorption is 872.2 BV/h, and the loading density is 0.202 g/cm3. A mixture of 2.5 mol/L NH4SCN with 0.1 mol/L NaOH is chosen as the gold (I) eluent, and the eluention flow rate is 96.9 BV/h. The conclusion is that the homemade fibers could be used inseries to extract the gold (I) from cyanide leaching solution.

Abstract: The research about the macro-inclusions of three processes: BOF→ LF→ CC, BOF→ RH→ CC and BOF→ LF→ RH→ CC, shows that: The types of inclusion are SiO2-Al2O3-CaO-TiO2-MnO, SiO2 and SiO2-Al2O3. The content of SiO2-Al2O3- CaO-TiO2-MnO in the three processes are 34.2%、23.5% and 27%; The content of SiO2 are 24.4%、47% and 27%; The content of SiO2-Al2O3 are 26.8%、17.6% and 9%. Large inclusion>300μm takes up 69.8%~85% of the total inclusion in billet in three technological processes, and the inclusion, containing K and Na, is the most; slag entrapment in mould is really serious. Considering the cleanliness and cost, the better technological process of MRT3-BA stamping steel is BOF→ RH→ CC.