Process for the production of articles made of a gamma-prime precipitation-strengthened nickel-base superalloy by selective laser melting (SLM)

A process for producing a crack-free three-dimensional article by selective laser melting (SLM), the process comprising:

• (a) preparing a powder layer, including a powder of a material including a gamma-prime precipitation-strengthened nickel-base alloy, with a regular and uniform thickness on a substrate plate of an SLM apparatus or on a previously processed powder layer;
• (b) melting the prepared powder layer by scanning with a focused laser beam an area corresponding to a cross section of the article according to a three-dimensional sliced model of the article, with calculated cross sections, stored in an SLM control unit of an SLM apparatus, the melting performed such that a laser power, focus diameter of the focal spot, and scan speed of the focused laser beam are adjusted to obtain heat dissipation welding resulting in a weld bead aspect ratio of depth to width smaller than 0.5 during the melting of the prepared powder layer, wherein the laser power is 50-150 W, the scan speed is 80-700 mm/s, the focus diameter is 0.1-0.5 mm, and a hatch distance for the laser is 0.01-0.5 mm and a laser operational mode for generating the laser beam is a continuous wave mode;
• (c) lowering the substrate plate by one layer thickness;
• (d) repeating (a) to (c) until reaching a final cross section according to the three-dimensional sliced model, and
• wherein, in (a), the gamma-prime precipitation-strengthened nickel-base alloy comprises more than 6 wt. % of [2 Al (wt. %)+Ti (wt. %)] and wherein the gamma-prime precipitation-strengthened nickel-base alloy comprises Ni, unavoidable impurities, and:
• 3.2-4.2 wt. % Al,
• 2.8-3.8 wt. % Ti,
• 14.5-17 wt. % Cr,
• 7.8-9.0 wt. % Co,
• 1.2-1.9 wt. % Mo,
• 2.1-3.5 wt. % W,
• 1.0-2.0 wt. % Ta,
• 0.5-1.5 wt. % Nb,
• <0.15 wt. % C, and
• <0.02 wt. % B.