Selective Laser Sintering of High Performance High Temperature Materials

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Date

1996

Authors

Das, S.
Harlan, N.
Beaman, J. J.
Bourell, D. L.

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Abstract

Hot Isostatic Pressing (HIP) of high performance metal parts is currently done using either a shaped metal container or a pre-fabricated ceramic mold depending on the part material and geometry. An alternative method of HIP encapsulation that allows complex part geometry, short cycle time and minima) potential for container-powder bed interaction is desired. Integral, fully dense metal skins with complex geometry can potentially be constructed by direct selective laser sintering (SLS). The advantages ofin-situ HIP encapsulation by direct SLS include the elimination of a secondary container material and any associated container-powder bed interaction, reduced pre-processing time and a short HIP cycle. Single and multi-layer specimens of Inconel625, Ti-6AI-4Vand 17-4 PH stainless steel were produced by direct SLS. Closed porosity in Inconel625 and 17-4 PH stainless steel samples ranged from 0 to 12% and area porosity from 0.5 to 20%, depending on the laser energy density. Direct SLS samples ofInconel 625 were subjected to helium leak testing and found to be impervious, with a leak rate less than lxl0-10 atm eels. These samples met the criteria for containerless hot isostatic pressing.

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