The evaporation and oxidation of zinc during the welding process was studied. The characteristics of microstructure and micro-hardness of the ZA alloy’s bond area that welded by TIG were investigated by using TEM, SE...The evaporation and oxidation of zinc during the welding process was studied. The characteristics of microstructure and micro-hardness of the ZA alloy’s bond area that welded by TIG were investigated by using TEM, SEM and other methods. The results show that, by using the same filler metal as the parent metal, zinc content in bond area is lower than that in the weld metal and the base metal. The main structure of the bond area is columnar dendrite, including Zn, Al 4Cu 9, CuTi 2, Al 7Cu 3Mg 6 phases. There are many changes of structure in the bond area. The structure near the weld is some tiny slice Zn and α-Zn. The structure near the parent metal is rather coarse but is still a little tiny than that of the parent metal. As the tiny structure of the heat affected zone has high hardness, it can strengthen the weld, and thus improve the mechanical properties of the welded joint.展开更多
The Zhangjiagang Bonded Area,founded on October 16, 1992 withthe approval of the State Council, isthe only bonded area serving inland riverharbours. It covers 4.1 square kilometres. Itis a free trade area employing th...The Zhangjiagang Bonded Area,founded on October 16, 1992 withthe approval of the State Council, isthe only bonded area serving inland riverharbours. It covers 4.1 square kilometres. Itis a free trade area employing the interna-tional practice combined with the Chinesecharacteristics. It adopts special policies whichare more flexible and preferential than thoseadopted by other SEZs and economic devel-opment zones.展开更多
Located in the Yangtze River Delta as a point connecting China’s coastal areas and the Yangtze River Valley, the Zhangjiagang Bonded Area-the only free-trade zone at an inland rivei port-was set up in October 1992 wi...Located in the Yangtze River Delta as a point connecting China’s coastal areas and the Yangtze River Valley, the Zhangjiagang Bonded Area-the only free-trade zone at an inland rivei port-was set up in October 1992 with the approval of the State Council. The area’s three main functional sections are trade, warehousing and export processing sections, supported by international financial services, real estate and administrative services. Covering展开更多
Investigations of technological characteristics and bonding mechanism of field-assisted bonding are done, which are for bonding of electrolytes (Pyrex glass) to monocrystal silicon and aluminum. The features of micros...Investigations of technological characteristics and bonding mechanism of field-assisted bonding are done, which are for bonding of electrolytes (Pyrex glass) to monocrystal silicon and aluminum. The features of microstructure and the distribution of the diffused elements in the bonding interface area are studied by means of SEM, EDX and XRD, and the influence of the technological factors on the bonding process is also studied. The model of 'metal-oxides-glass' of bonding structure and ions diffusion and bonding in the condition of electrical field-assisted are indicated.展开更多
Roller Compacted Concrete (RCC) has gained favorable recognition in hydropower and water resource dam construction. With optimization in construction technology and materials used for RCC Dams, cost is no longer a maj...Roller Compacted Concrete (RCC) has gained favorable recognition in hydropower and water resource dam construction. With optimization in construction technology and materials used for RCC Dams, cost is no longer a major disadvantage as compared to environmental impact, that is, wildlife habitat disruption. In as much as it has become optimal for investment in hydropower dam construction, the scourge for dam failure is still eminent, which is as a result of excessive seepage compromising the integrity of the mechanical properties of the dam. The aim of the paper is to highlight successful application methods in joint bonding to avoid excessive seepage and reduce the autogenous healing to a few years of operation. In view of optimization, this paper presents a comprehensive study on the influences of interlayer joints bonding quality from RCC mix performances and how it consolidates the RCC layers to withstand the shear strength along the interface, especially on the high dams. The case study is the RCC dam at the 750 MW Kafue Gorge Lower Hydropower Station. The scope of the study reviews the joint type judged by Modified Maturity Factor (MMF) with joint surface long time exposed in regions with dry and high temperature, technical measures of layer bonding quality control under condition of long time joint surface exposure, effects of joints shear strength and impermeability of the RCC layers when under the conditions of plastic and elasticity. The subtle observations made during the dam construction phases were with respect to the optimal use of materials in relation to RCC mix designs and the basis for equipment calibration for monitoring important data that can be referenced during analysis of shear forces acting on the RCC dam over time.展开更多
文摘The evaporation and oxidation of zinc during the welding process was studied. The characteristics of microstructure and micro-hardness of the ZA alloy’s bond area that welded by TIG were investigated by using TEM, SEM and other methods. The results show that, by using the same filler metal as the parent metal, zinc content in bond area is lower than that in the weld metal and the base metal. The main structure of the bond area is columnar dendrite, including Zn, Al 4Cu 9, CuTi 2, Al 7Cu 3Mg 6 phases. There are many changes of structure in the bond area. The structure near the weld is some tiny slice Zn and α-Zn. The structure near the parent metal is rather coarse but is still a little tiny than that of the parent metal. As the tiny structure of the heat affected zone has high hardness, it can strengthen the weld, and thus improve the mechanical properties of the welded joint.
文摘The Zhangjiagang Bonded Area,founded on October 16, 1992 withthe approval of the State Council, isthe only bonded area serving inland riverharbours. It covers 4.1 square kilometres. Itis a free trade area employing the interna-tional practice combined with the Chinesecharacteristics. It adopts special policies whichare more flexible and preferential than thoseadopted by other SEZs and economic devel-opment zones.
文摘Located in the Yangtze River Delta as a point connecting China’s coastal areas and the Yangtze River Valley, the Zhangjiagang Bonded Area-the only free-trade zone at an inland rivei port-was set up in October 1992 with the approval of the State Council. The area’s three main functional sections are trade, warehousing and export processing sections, supported by international financial services, real estate and administrative services. Covering
基金This project is supported by Foundation of Taiyuan University of Technology "211" Project, China (No.20304006).
文摘Investigations of technological characteristics and bonding mechanism of field-assisted bonding are done, which are for bonding of electrolytes (Pyrex glass) to monocrystal silicon and aluminum. The features of microstructure and the distribution of the diffused elements in the bonding interface area are studied by means of SEM, EDX and XRD, and the influence of the technological factors on the bonding process is also studied. The model of 'metal-oxides-glass' of bonding structure and ions diffusion and bonding in the condition of electrical field-assisted are indicated.
文摘Roller Compacted Concrete (RCC) has gained favorable recognition in hydropower and water resource dam construction. With optimization in construction technology and materials used for RCC Dams, cost is no longer a major disadvantage as compared to environmental impact, that is, wildlife habitat disruption. In as much as it has become optimal for investment in hydropower dam construction, the scourge for dam failure is still eminent, which is as a result of excessive seepage compromising the integrity of the mechanical properties of the dam. The aim of the paper is to highlight successful application methods in joint bonding to avoid excessive seepage and reduce the autogenous healing to a few years of operation. In view of optimization, this paper presents a comprehensive study on the influences of interlayer joints bonding quality from RCC mix performances and how it consolidates the RCC layers to withstand the shear strength along the interface, especially on the high dams. The case study is the RCC dam at the 750 MW Kafue Gorge Lower Hydropower Station. The scope of the study reviews the joint type judged by Modified Maturity Factor (MMF) with joint surface long time exposed in regions with dry and high temperature, technical measures of layer bonding quality control under condition of long time joint surface exposure, effects of joints shear strength and impermeability of the RCC layers when under the conditions of plastic and elasticity. The subtle observations made during the dam construction phases were with respect to the optimal use of materials in relation to RCC mix designs and the basis for equipment calibration for monitoring important data that can be referenced during analysis of shear forces acting on the RCC dam over time.
