Advanced Materials Research Vol. 813

Abstract: 3-ply Cu-Ni-Zn/Cu-Cr/Cu-Ni-Zn clad composite plates were prepared by roll bonding at 823K and their properties were characterized. No intermetallic compounds were observed at Cu-Ni-Zn/Cu-Cr interfaces in the as-rolled and heat-treated Cu/Ni-Zn/Cu-Cr/Cu-Ni-Zn clad plates. The strength of as-rolled clad plate reached up to 420MPa with the ductility of 13%. After heat treatment at 723K for 1.5 hours, the strength of Cu-Ni-Zn/Cu-Cr/Cu-Ni-Zn clad composite plate dropped to 340 MPa and the ductility increased to 20%. With annealing at 723K, there is no drastic drop of the stress before final fracture, meaning three plates were bonded together until the last part of the stress-strain curve. The peak of the conductivity (>70% of IACS) was attained after aging for 1.5 hrs, compatible with the typical peak aging condition of Cu-Cr alloy.

Abstract: The microstructure and mechanical behaviors of the Al-Mg-B ternary alloy have been investigated in order to fabricate a composite system composed of (Al,Mg)B₂ in a Al-Mg matrix. Several Al-Mg-B ternary alloy compositions were selected for identification of borides and matrix formation during solidification. The in-situ (Al,Mg)B₂ phase was developed in an eutectic matrix of Al₈Mg₅ and Al, and formed in the location of inter and intra the Al dendritic region, indicating that the formation of (Al,Mg)B₂ was developed at the initial solidification process. Dominating factors for controlling the (Al,Mg)B₂ phase and mechanical behaviors are discussed in terms of structural identifications.

Abstract: The molecular dynamics simulation studies on the microstructure evolution properties of amorphous Ca₇Mg₃ alloy during the isothermal annealing have been performed. The simulated structure factor S(q) of Ca₇Mg₃ is well agreed with the experimental data. Results indicate that the metallic glass of Ca₇Mg₃ alloy is relaxed into amorphous structure of greater stability in which much more icosahedron structures is formed; interestingly, it is also found that the short short-range order has no change, while the short-range order of the system increases during the isothermal annealing process.

Abstract: The metallurgy reactions in the weld pool were analyzed with the application of reaction kinetics. Furthermore a formula to quantificationally calculate the amount of Mg2Si was generated. By means of calculating the thermodynamic condition of the reaction and combined with the verification testing, this article indicates that the metallurgical product Mg2Si was created in the liquid weld pool but not separated out from the arborescent crystal during its solid state. This thesis summarizes the precipitation mechanism of Mg2Si and explains the configuration, amount and location where Mg2Si was separated out by analyzing the phase diagrams and constitution diagrams. Relevant data suggests that: the content of Mg2Si is slightly less than Mg.

Abstract: The circular economy (CE) is a new development strategy for China to alleviate the contradiction between rapid economic growth and the shortage of raw materials and energy. As the basic material, steel is a key driver of the world's economy. Therefore, it is essential to set up CE indicators system to understand the mechanism of steel resources role in the circular economy. In this paper, a national level material flow evaluation framework based on CE theory is presented at the first. Then steel resources national lifetime cycle diagram is built based on dynamic Material Flow Analysis (MFA) method considering the steel lifetime circular flow characteristics. Under the guidance of this diagram, the material flow results of various stages (such as production process, fabrication & manufacturing process, in-use process, etc.) of steel lifetime cycle between 2001-2010 in China is obtained, including the end-of-life scarp amount of nine downstream industries. The results indicate that China steel resources has made gratifying achievements in improving productivity, reducing energy consumption and related pollution emission, but the degree of overall circulation remains to be improved urgently. In the end, a sketch of the future relevant policy recommendations are provided.

Abstract: In this study a plate form of Ti-50.7at.%Ni was subjected to solution annealing at 800°C and 900°C for one hour followed by ageing at 300°C and 400°C for 4 hours respectively in order to investigate the effect of solution annealing and low temperature ageing on the microstructures and superelastic behaviour. It was found that the formation of Ti₃Ni₄ precipitates on the samples aged at 300°C and 400°C influences superelasticity differently. Increasing the testing temperature up to 38°C generally increases the superelasticity of samples for all heat treatment conditions compared to those tested at 22°C, however the sample solution annealed at 900°C give better superelasticity at 22°C due to excessive plastic deformation at higher temperature.

Abstract: The paper tries to address the common challenges that many small and medium enterprises (SMEs) are facing: the manufacturing data integration with a collaborative manufacturing environment with low volume and high mix production orders. The research focus is on the interoperability between the existing and a new ERP system, as well as the collaboration scheme among different suppliers and partners in a supply chain model.

Abstract: In this study, strength of Cu-9Fe-1.2X (X 5 Ag or Cr) microcomposite disks obtained HPT(high pressure torsioning) have been investigated. The dendrite arms were aligned along the drawing direction and elongated into filaments. The filament spacings were found to small in Cu-9Fe-1.2Ag compared to those of other microcomposites. The ultimate tensile strength of the Cu-Fe-Ag microcomposites were higher than those of Cu-Fe-Co and Cu-Fe-Ni microcomposites, suggesting the strengthening of the matrix is more effective than the strengthening of the filaments in strengthening the microcomposites. The strength of Cu-Fe-Xi microcomposites increased more rapidly when the finer microstructure was developed by the plastic flow and refinement of filaments by the effect of strong Cu matrix strengthened by Ag atoms. With increase of strain up to 7 rotations, the second phase lamella was observed to be fragmented by HPT rotations and small second phase particles were observed.

Abstract: Ring compression tests on the oxidized Zr-1.1Nb-0.05Cu cladding tubes were performed to examine the mechanical reliability of Zr-Nb-Cu cladding tubes. In compression of the non-oxidized cladding tubes, large load drop associated with the cladding failure appeared at the total displacement of 6.3 mm. After oxidation at 600°C for 24 hrs and 700°C for 3 hrs, small drop of load resulting from small cracks in the thin oxide film was observed at the total displacement of 1.0 mm. After oxidation at 700°C for 24hrs, load was extremely low, but catastrophic fracture occurred at the total displacement of 6.2~6.5 mm. The oxide of Zr-1.1Nb-0.05Cu cladding tubes formed at high temperature apparently causes the premature failure of tubes.

Abstract: Preparation of the tundish coverture fluxes by the blast furnace slag can recycle utilization of solid wastes discharged from iron and steel industry. Calcium fluoride and magnesia can play an important role for the basic performance of tundish coverture fluxes. The impact on the melting temperature, viscosities and surface tension of the tundish coverture fluxes from the content of calcium fluoride and magnesia were studied. The results showed that: When the content of CaF₂ increased from 10% to 25%, the melting temperature, the viscosity and the surface tension were decreased by 50°C, 0.3 Pa·S and 0.039 N/m respectively. The viscosity was brought down of 0.02 Pa·S, the surface tension was increased by 0.03 N/m, and the difference between the lowest and highest melting temperature was about 3°C when the content of MgO changed from 5% to 11%.