Material Health of NiCrBSi Alloy Parts Produced via the Laser Powder Bed Fusion Process

Abstract

Laser powder bed fusion (L-PBF) is a novel process representing a possible solution for producing resistant parts using NiCrBSi hard-facing nickel alloys with complex geometry. Process parameters for more common alloys are explored with a standard Renishaw AM400 device (Renishaw, Wotton-under-Edge, UK) and an SLM Solution 250 device (SLM Solutions Group AG, Lübeck, Germany) modified with a baseplate preheated at high temperatures (300 °C and 500 °C). Laser remelting is also investigated in hopes of further improving material health. The origin of the main defects is studied. A lack of fusion is likely to be generated by spatters ejected from the melting pool while cracks are induced by the alloy’s lack of toughness. Using image analyses, those defects are quantified and correlated with processing parameters. Lack of fusion and total crack length decrease with an increase in baseplate’s preheating temperature. However, crack width increases with preheating temperature. Therefore, via a careful optimization of process parameters, samples with a surface density of 99% and narrow cracks are obtained.

Keywords

• NiCrBSi
• nickel superalloy
• additive manufacturing
• L-PBF
• material health
• X-ray tomography