S.Y. Gao
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Y.Z. Zhang
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L.K. Shi
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B.L. Du
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M.Z. Xi
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H.Z. Ji
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null
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null
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null
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null
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null
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null
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null
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金属学报(英文版)
Laser direct deposition (LDD) of metallic components is an advanced technology of combining CAD/CAM (computer aided design/computer aided manufacturing), high power laser, and rapid prototyping. This technology uses laser beam to melt the powders fed coaxially into the molten pool by the laser beam to fabricate fully dense metallic components. The present article mainly studies the LDD of Ti-6Al-4V alloy, which can be used to fabricate aircraft components. The mechanical properties of the Ti-6Al-4V alloy, fabricated by LDD, are obtained using the tension test, and the oxygen content of used powders and deposited specimens are measured. In the present article, it can be seen that the mechanical properties obtained using this method are higher than the ones obtained by casting, and equal to those got by wrought anneal. One aircraft part has been made using the LDD process. Because of this aircraft part, with sophisticated shape, the effect of the laser scanning track on the internal soundness of the deposited part was discussed.
关键词:
laser direct deposition
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null
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W. Chen
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Y.Z. Zhang
,
C.J. Zhang
,
L.G. Zhu
金属学报(英文版)
The aim of this study is to simulate the solidification process of beam blank continuous casting, and then find the reasons for the typical defects of the beam blank. A two-dimensional transient coupled finite element model has been developed to compute the temperature and stress profile in beam blank continuous casting. The enthalpy method is used in the heat conduction equation. The thermo-mechanical property in the mushy zone is taken into consideration in this calculation. It is shown that at the mold exit the thickness of the shell has its maximum value at the flange tip and its minimum value at the fillet. The temperature has a great fluctuation on the surface of the beam blank in the secondary cooling zone. At the unbending point, the surface temperature of the web is in the brittleness temperature range under the present condition. To ensure the quality, it is necessary to weaken the intensity of secondary cooling. At the mold exit the equivalent stress and strain have higher values at the flange tip and at the web. From the spray 1 to the unbending point, the maximum values of stress and strain gradually move to the internal section of the flange tip and the web. However, whenever, there are bigger stress and strain values near the flange tip and the web than in the other parts, it must be very easy to generate cracks at those positions. Now, online verification of this simulation has been developed, which has proved to be very useful and efficient to instruct the practical production of beam blank continuous casting.
关键词:
beam blank
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