Papers by Keyword: Metal

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Authors: Andreas Krause, Hanns Kache, Georg Ullmann
Abstract: The early detection of defects in forged parts offers economical advantages due to the possibility of sorting them out of the process chain betimes. Hence, no further production costs are occurred by those parts. However, the detection of defects during forging processes is not state of the art. Usually defects of forged parts which are often not obvious and therefore cannot be identified by the press operator are detected by measurements after cooling or later by the customer. In both cases costs occur. Due to the rough conditions in forging shop floors (e. g. high temperatures and forces) the integration of sensors monitoring the forging process is hardly viable. Within the presented research project an in-situ forging process monitoring system is developed which works without sensors in the forging tool and shows results on the process quality directly after forging. A system consisting of two independent concepts (defect-identification and filling-identification) is developed to detect typical forging process failures. On the one hand the defect-identification is able to detect e.g. wrong press energy or insert-position. On the other hand the filling-identification aims to detect, if the cavity is completely filled by the work-piece. Both concepts work in real-time with the help of a computer and a screen visualising the results. One the one hand this paper presents the results of forging trials using the defect-identification and evaluates its capability. On the other hand the concept for the filling identification is presented.
Authors: Zhi Jun Cao, Jia Chen Liu, Li Bin Liu, Hao Ye, Yan Qiu Wei
Abstract: A new approach was developed for surface modification of metallic surface. By treating nano-zirconia particles and metal surface in different charge state, nano-zirconia particles can be dispersedly inlaid in metal surface owing to electrostatic and nanometer effects. By using this method, metal components of complex shapes, especially those having inside surfaces, might be easily improved, i.e., enhanced surface hardness and wear rate.
Authors: Xiang Dong Ma, Xin Yang Wang, Ji Wen Li, Shi Zhong Wei
Abstract: Brazing with active filler alloys containing some active elements, which promotes wetting of ceramics surfaces, is one of the most widely methods for joining ceramics to metals. The joints formed by brazing A12O3 to metal by using copper-titanium-nickel (Cu-Ti-Ni) as brazing filler were investigated. The metals/ceramics joints were produced at a vacuum level of 10-2-10-3 Pa at 1273K, using a constant holding time of 10 min. The surfaces were studied both morphologically and structurally using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction analysis (XRD). In the brazing process, copper and titanium in the braze alloy form a series of reaction products. The formation of Ti3Cu3O and Ti2Ni at the interface is characteristic of these joints. The estimated free energies of formation of the Ti3Cu3O and Ti2Ni are -119kcal/mol and -245.92 kJ ~-263.78kJ/mol at 1200~1288K respectively. The highly negative values for the free energies of formation suggest that these compounds are thermodynamically stable.
Authors: Mehdi Soodi, S.H. Masood, Milan Brandt
Abstract: Laser cladding is a thermal process for depositing a metallic alloy on to a parent metal to repair corrosion, erosion, wear or other physical damage. The present work studies the effects of the laser cladding process on the integrity of metal substrates and the bond between the cladding layer and the base metal. It also evaluates some physical characteristics of the cladding layer, in this case grade 420 stainless steel. The research compares the work with Tungsten Inert Gas (TIG) welding and concludes that, due to the small size of the heat-affected zone, this laser cladding process does not adversely affect the physical properties of the metallic substrates.
Authors: Xiao Ling Zheng, Ming Song Zhang, Min You, Hai Zhou Yu, Zhi Li
Abstract: The normal stress distributed in the mid-bondline of the adhesively bonded joint under cleavage loading was investigated using the elastic finite element method (FEM) and the strain gauges method to reveal the real normal stresses distribution in the metal-to-metal joint while the load was increased. The results from the finite element analysis (FEA) showed that there is always a peak stress of the normal stress Sy in the mid-bondline occurred at a point close to the loading pin axis. When the load was increased from 0.5 kN to 3 kN, there was also a point located at about x = 16mm along the length of specimen where there is without any normal stress at all. The result of stress Sy from the FEA is nearly the same as that one obtained from the strain gauges method. It was also found that there was a evidently hardness change in the bonded zone of the adherend made from structural steel or pure copper, which can be used to explain the procedure of the joint and discuss the distribution model of the normal stress Sy in the joint under the cleavage loading.
Authors: Pannaporn Pintavirooj, Ponlakit Jitto, Nida Chaimoon
Abstract: This research objective was to study a synthesis of metal ZSM-5 catalyst by adding the metals into the HZSM-5 and NaZSM5. Metals used were silver (Ag), Zinc (Zn), Iron (Fe), and Molybdenum (Mo) by allegorizing with the calcined and without calcined catalyst. The catalyst structure was showed by Scanning Electron Microscopy (SEM). Each catalyst was determined in terms of element quantity by the Energy Dispersive X-Ray Fluorescence Spectrometer. The results of this research were showed that every type of metal can exchange on Hydrogen or Sodium of HZSM-5 and NaZSM-5, respectively. Molybdenum (Mo), Zinc (Zn), Iron (Fe) and Silver (Ag) were added into HZSM-5, then the ratio of Si:Al:Metals were 9.24:0.49:1, 48.21:2.66:1, 85.73:4.55:1 and 17.53:0.93:1, respectively. While the Mo, Zn, Fe, and Ag were added into NaZSM-5 to be a complex catalyst. The ratios were 10.11:0.53:1, 43.93:2.44:1, 93.19:5.35:1 and 11.50:0.65:1, respectively. The conclusions indicated that Mo was the best metal that can be added to ZSM-5, while Fe was the less. NaZSM-5 was more efficiency for adding each metal than HZSM-5.
Authors: S. Chenna Krishna, K. Thomas Tharian, Bhanu Pant, Ravi S. Kottada
Abstract: Among the copper alloys, the Cu-3Ag-0.5Zr alloy is one of the potential candidates for combustion chamber of liquid rocket engine because of its optimum combination of high strength with thermal conductivity. The present study is a detailed characterization of microstructure, strength, and electrical conductivity during the aging treatment. The aging cycle for Cu-3Ag-0.5Zr alloy after the solution treatment (ST) was optimized to obtain higher hardness without compromising on electrical conductivity. The precipitates responsible for strengthening in aged samples are identified as nanocrystalline Ag precipitates with an average diameter of 9.0±2.0 nm.
Authors: Guo Min Lin, Li Xia Peng, Yu Feng Zhao
Abstract: The application of two representative laser surface treatments technologies which are laser shock processing technology and laser coating treatment technology are described. The application of laser shock processing in the fields of aero engine disc, wing panel formation, structural welding and strengthening, nuclear power station pressure container strengthening etc and also evaluates the effects are analyzed. The applications of laser coating treatment in the field of aeronautic manufacturing are analyzed in detail. The development direction of laser shock processing and laser coating treatment are indicated finally.
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