The Experts below are selected from a list of 63 Experts worldwide ranked by ideXlab platform

Tomokatsu Aizawa - One of the best experts on this subject based on the ideXlab platform.

  • interfacial microstructure and strength of steel aluminum alloy lap joint fabricated by magnetic pressure Seam Welding
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2007
    Co-Authors: Shinji Kumai, Takashi Arai, Tomokatsu Aizawa
    Abstract:

    Lap joining of low carbon steel (SPCC)/A6111 aluminum alloy was carried out using the magnetic pressure Seam Welding method. Interfacial microstructure, in particular, an intermediate layer formed at the weld interface was precisely examined using TEM. Tensile tests were also performed for the lap joints. Lap joining was successfully attained in several microseconds with no temperature increase. Weld interface of the lap joint showed wavy morphology and the intermediate layer was observed along the wavy interface. These microstructures are similar to that of the explosive weld lap joint. TEM observation revealed that the intermediate layers consist of fine aluminum grains (around 100 nm) and more finely dispersed intermetallic particles. A6111 matrix close to the weld interface also exhibited extremely refined grain structure. The bonding strength of the joint was quite high and it failed at the parent plate. The multi-phase intermediate layer and grain-refined aluminum layer are considered to be the origin of high interfacial bonding strength of the lap joint.

  • interfacial microstructure of magnetic pressure Seam welded al fe al ni and al cu lap joints
    Materials Science Forum, 2006
    Co-Authors: Mitsuhiro Watanabe, Shinji Kumai, Tomokatsu Aizawa
    Abstract:

    A new Welding method, magnetic pressure Seam Welding, was used to lap join dissimilar metals (Al-Fe, Al-Ni and Al-Cu). The circuit for magnetic pressure Seam Welding consists of a capacitor, an electric discharge gap switch, and a plate-type coil. The overlapped metal plates are placed over the coil. When an impulse current from an energy-storage capacitor bank passes through the coil, a high-density magnetic flux is suddenly generated around the coil. The generated high-density magnetic flux lines cross the end of the overlapped plates. Eddy currents are induced mainly inside the Al plate because it has a high electrical conductivity. Both the Joule heat generated in the plates and the magnetic pressure applied from the Al side promote the joining of the lapped plates. The Welding is normally achieved within 10 μs. This results in very little microstructural change in the parent plates aside from the area around the weld interface. Strong lap joints were obtained for every metal combination and no tensile fracture took place in the weld region. A characteristic wavy morphology was observed at the weld interface. An intermediate phase layer was also observed at the weld interface. TEM observation revealed that the intermediate layer consisted of fine Al grains and intermetallic compound particles dispersed among the Al grains. The growth direction of the wave, the Welding condition dependency of the wavelength and the amplitude of the interfacial wave were intensively investigated in order to clarify the Welding mechanism of this method.

Shinji Kumai - One of the best experts on this subject based on the ideXlab platform.

  • interfacial microstructure and strength of steel aluminum alloy lap joint fabricated by magnetic pressure Seam Welding
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2007
    Co-Authors: Shinji Kumai, Takashi Arai, Tomokatsu Aizawa
    Abstract:

    Lap joining of low carbon steel (SPCC)/A6111 aluminum alloy was carried out using the magnetic pressure Seam Welding method. Interfacial microstructure, in particular, an intermediate layer formed at the weld interface was precisely examined using TEM. Tensile tests were also performed for the lap joints. Lap joining was successfully attained in several microseconds with no temperature increase. Weld interface of the lap joint showed wavy morphology and the intermediate layer was observed along the wavy interface. These microstructures are similar to that of the explosive weld lap joint. TEM observation revealed that the intermediate layers consist of fine aluminum grains (around 100 nm) and more finely dispersed intermetallic particles. A6111 matrix close to the weld interface also exhibited extremely refined grain structure. The bonding strength of the joint was quite high and it failed at the parent plate. The multi-phase intermediate layer and grain-refined aluminum layer are considered to be the origin of high interfacial bonding strength of the lap joint.

  • interfacial microstructure of magnetic pressure Seam welded al fe al ni and al cu lap joints
    Materials Science Forum, 2006
    Co-Authors: Mitsuhiro Watanabe, Shinji Kumai, Tomokatsu Aizawa
    Abstract:

    A new Welding method, magnetic pressure Seam Welding, was used to lap join dissimilar metals (Al-Fe, Al-Ni and Al-Cu). The circuit for magnetic pressure Seam Welding consists of a capacitor, an electric discharge gap switch, and a plate-type coil. The overlapped metal plates are placed over the coil. When an impulse current from an energy-storage capacitor bank passes through the coil, a high-density magnetic flux is suddenly generated around the coil. The generated high-density magnetic flux lines cross the end of the overlapped plates. Eddy currents are induced mainly inside the Al plate because it has a high electrical conductivity. Both the Joule heat generated in the plates and the magnetic pressure applied from the Al side promote the joining of the lapped plates. The Welding is normally achieved within 10 μs. This results in very little microstructural change in the parent plates aside from the area around the weld interface. Strong lap joints were obtained for every metal combination and no tensile fracture took place in the weld region. A characteristic wavy morphology was observed at the weld interface. An intermediate phase layer was also observed at the weld interface. TEM observation revealed that the intermediate layer consisted of fine Al grains and intermetallic compound particles dispersed among the Al grains. The growth direction of the wave, the Welding condition dependency of the wavelength and the amplitude of the interfacial wave were intensively investigated in order to clarify the Welding mechanism of this method.

Takashi Arai - One of the best experts on this subject based on the ideXlab platform.

  • interfacial microstructure and strength of steel aluminum alloy lap joint fabricated by magnetic pressure Seam Welding
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2007
    Co-Authors: Shinji Kumai, Takashi Arai, Tomokatsu Aizawa
    Abstract:

    Lap joining of low carbon steel (SPCC)/A6111 aluminum alloy was carried out using the magnetic pressure Seam Welding method. Interfacial microstructure, in particular, an intermediate layer formed at the weld interface was precisely examined using TEM. Tensile tests were also performed for the lap joints. Lap joining was successfully attained in several microseconds with no temperature increase. Weld interface of the lap joint showed wavy morphology and the intermediate layer was observed along the wavy interface. These microstructures are similar to that of the explosive weld lap joint. TEM observation revealed that the intermediate layers consist of fine aluminum grains (around 100 nm) and more finely dispersed intermetallic particles. A6111 matrix close to the weld interface also exhibited extremely refined grain structure. The bonding strength of the joint was quite high and it failed at the parent plate. The multi-phase intermediate layer and grain-refined aluminum layer are considered to be the origin of high interfacial bonding strength of the lap joint.

Yih Fong Tzeng - One of the best experts on this subject based on the ideXlab platform.

  • Parametric analysis of the pulsed Nd:YAG laser Seam-Welding process
    Journal of Materials Processing Technology, 2000
    Co-Authors: Yih Fong Tzeng
    Abstract:

    The present paper includes the descriptions of the overlap theory and the Welding mechanism, the formulation of relevant mathematical equations, and the parametric analysis of the pulsed laser Seam-Welding (PLSW) process. The PLSW process is simplified by strategic control of identified major process parameters, such as the mean laser power, the average peak power density, the pulse energy and the traversing speed. An experimental analysis has also been made in the study to investigate systematically the effects of the above-mentioned laser parameters on heat flow so that the controlled pulsed laser Welding of materials can be carried out.

Wagne De Rossi - One of the best experts on this subject based on the ideXlab platform.

  • pulsed nd yag laser Seam Welding of aisi 316l stainless steel thin foils
    Journal of Materials Processing Technology, 2010
    Co-Authors: Vicente Afonso Ventrella, Jose Roberto Erretta, Wagne De Rossi
    Abstract:

    Experimental investigations were carried out using a pulsed neodymium:yttrium aluminum garnet laser weld to examine the influence of the pulse energy in the characteristics of the weld fillet. The pulse energy was varied from 1.0 to 2.25 J at increments of 0.25 J with a 4 ms pulse duration. The base material used for this study was AISI 316L stainless steel foil with 100m thickness. The welds were analyzed by optical microscopy, tensile shear tests and microhardness. The results indicate that pulse energy control is of considerable importance to thin foil weld quality because it can generate good mechanical properties and reduce discontinuities in weld joints. The ultimate tensile strength of the welded joints increased at first and then decreased as the pulse energy increased. The process appeared to be very sensitive to the gap between couples. © 2010 Elsevier B.V. All rights reserved.