Residual stresses in laser-deposited metal parts

    Authors

    F. J. Kahlen;A. Kar

    Comments

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    Abbreviated Journal Title

    J. Laser Appl.

    Keywords

    residual stress; tensile strength; rapid manufacturing; prototyping; direct metal deposition; part fabrication; layer deposition; stress; modeling; part dimension modeling; attenuation coefficient; Materials Science, Multidisciplinary; Optics; Physics, Applied

    Abstract

    Several laser-based techniques to fabricate parts by depositing metals, ceramic powders, or a combination thereof have been developed in recent years. These fabrication techniques are incomplete and not fully useful to an operator without any predictive capability to calculate the geometries of the fabricated parts or equations to calculate their expected yield and ultimate strengths. Data concerning the energy transfer from the processing laser beam to the material powder, such as the metal vapor-plasma plume temperature and plume absorption coefficient, the efficiency of laser energy transfer and mathematical analysis for the thermal and dimensional process characteristics are unavailable. Also, the characterization of the mechanical properties of such laser-fabricated parts has just begun. A one-dimensional model to calculate the thermal and dimensional process characteristics is developed. The model accounts for the transmission of the laser beam through the plume, energy transfer in the molten phase, and the Stefan conditions at the solid-liquid and liquid-vapor interfaces. The yield and ultimate strengths of laser-fabricated stainless steel (SS 304) parts have been measured. A mathematical model is developed accounting for directionally preferred solidification to calculate the residual stresses generated in the part during solidification. (C) 2001 Laser Institute of America.

    Journal Title

    Journal of Laser Applications

    Volume

    13

    Issue/Number

    2

    Publication Date

    1-1-2001

    Document Type

    Article

    Language

    English

    First Page

    60

    Last Page

    69

    WOS Identifier

    WOS:000168085200003

    ISSN

    1042-346X

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