Advanced Materials Research Vol. 902

Abstract: As the strength of structural steels is increasing, the performance of fire resistance should be evaluated clearly and suggested. While their application has been expanded, the evaluation of the fire resistance is inclined to adopt that derived from ordinary strength steels. In order to compare the fire resistance performance of high strength structural steels at high temperature, databases such as mechanical and thermal properties at elevated temperature were compared with those of Eurocode 3. After comparison, it is recommended that the passive protective material is more needed than those for the ordinary strength structural steels to meet the fire resistance requirement.

Abstract: The high silicon electrical steel composite plate, which contains Q235 low carbon steel and 10%Si ferrosilicon alloy, is fabricated by coat casting and hot rolling. The bonding strength, microstructure and distribution of elements of the coating and core layers are analysed by the photographs of metallographic phase and EDS. Experimental results show that the high silicon composite plate could carry out lager plastic deformation by conventional hot mill after the 10%Si ferrosilicon alloy coated by Q235 low carbon steel in the vacuum induction furnace. The uniform distribution of elements could be achieved through the diffusion annealing process after the stage of hot rolling processing. This study provides a referable method to produce the 6.5wt% high silicon electrical steel plates.

Abstract: This research developed a feedback control system of laser compensation for the rapid prototyping (RP) machine using layer-wise slurry deposition and selective laser sintering (SLS). The slurry was prepared by silica power and silica sol with 60 and 40 wt.% with suitable rheological properties for 0.1 mm layer deposition. Four ceramics for comparison of the formability of fabricated ceramic green parts with/without the feedback control system of laser energy density for models were designed With this laser feedback control, batter quality ceramic green parts can be manufactured and the rapid prototyping machine with steady laser energy radiated on slurry layer was achieved. Experimental results validate the well performance of the measuring laser power and feedback control system.

Abstract: In the present investigation friction stir processing (FSP) is carried out using multipass FSP on a 5086 aluminum alloy to modify microstructure and mechanical properties. Two processing conditions P1 and P2 were used, P1 is carried out at constant rotation speed of 1025 rpm and at a traverse speed of 50 mm/min, P2 is carried out at constant rotation speed of 720 rpm and at a traverse speed of 155 mm/min. Inhomogeneous microstructural distribution was observed across the processed zone. EBSD analysis has been done to evaluate the microstructure. Overlapping passes is showing same grain size in the FSPed material. Material processed using P2 processing condition is showing maximum superplastic ductility. The bulk material produced due to multipass FSP seems to be good for superplastic forming applications.

Abstract: In the present investigation experimental and analytical characterization of the high temperature (superplastic) deformation of AA5083 alloy was carried out. Uniaxial tensile test was performed in a temperature range of 748 823K at different initial strain rates. Superplasticity is the ability of polycrystalline materials to exhibit, in a relatively uniform/isotropic manner, very large tensile elongations prior to failure, under appropriate conditions of temperature and strain rates. The phenomenon of superplasticity arising due to specific microstructural conditions is commonly referred to as "structural" superplasticity or "micrograin" superplasticity.

Abstract: Although second harmonic generations from gold- and copper-nanowires have been the subject of extensive studies, a complete understanding of the mechanism of the enhancement is still missing. The aim of review article is to address these issues by performing systemic studies of mechanism of the resonant enhancements between gold- and copper-nanowires in terms of surface reconstruction and relativistic effect, and implements these types of candidate for the potential applications in optical communications and optical devices.

Abstract: This paper is focused on the numerical simulation of a new technology of small size iron ore sintering machine using gaseous fuel and oxygen injections to produce high quality of sinter product for the blast furnace operation. The proposed methodology is to partially replace the solid fuel (coke breeze) by steelworks gases in a compact machine to enhance heat and mass transfer. A multiphase mathematical model based on transport equations of momentum, energy and chemical species coupled with chemical reaction rates and phase transformations is proposed to analyze the inner process parameters. A base case representing a possible actual industrial operation of the sintering machine is used in order to compare different scenarios of possible operations which represents advanced operations techniques. The model was used to predict four cases of fuel gas utilization: a) 3% of the wind boxes inflow from N01-N10 wind boxes of natural gas (NG) and oxygen, b) same condition with coke oven gas (COG) and c) mixture of 80% COG and 20% blast furnace gas (BFG). The model predictions indicated that for all cases, the sintering zone is enlarged and the solid fuel consumption is decreased about 12kg/t of sinter product for the best combination. In order to maximize the steelworks gas utilization it is recommended the use of mixture of COG and BFG with optimum inner temperature distribution within a compact sintering machine, which enhance the productivity and obviously, decrease the investment cost of the sintering facilities.

Abstract: Sulfur poisoning effect on the electrochemical performance and long-term durability of SOFC cathode has been investigated for La_0.6Sr_0.4Co_0.2Fe_0.8O₃ (LSCF) by Galvanic Current Interruption (GCI) technology. Cell performance was measured supplying with SO₂-containing air to the cathode under a constant current density of 200 mA cm^-2. At 800 °C, LSCF cathode showed low tolerance to the sulfur poisoning. SO₂ tends to react with strontium in LSCF material resulting in the formation of SrSO₄ in the cathode. This reaction gave rise to microstructural change in the cathode and caused gradual degradation of cell performance.

Abstract: Laser direct deposition of fully density metallic components is an advanced technology directly manufacturing metallic components to use a combining technology of rapid prototyping and high power laser cladding. Now researches have indicated that the laser direct deposition of titanium components is most definitely applied domain for this technology, and particularly obvious economic effects can be achieved in the field of manufacturing titanium aerial components. The present paper directs toward the laser direct deposition of Ti-6Al-4V alloy analyzed pattern features of molten pool and microstructure features of single-track build, multi-tracks overlap build, packing build. Through analysis, the bonding condition between cladding track and substrate has been disclosed, and the microstructure features in as-deposited zone and heat-affected zone have been indicated, as well as the influence of the overlap rate, track number of the multi-track overlap, and manner of the packing build on as-deposited microstructures has been explained.