By Konstantinos Georgilas
Background
Additive manufacturing of Alloy 718 has been extensively utilised to manufacture engineering components. Alloy 718 is a nickel-iron base superalloy that requires heat treatment to achieve final working properties. Alloy 718 is of special interest for the aerospace and oil & gas sector due to its excellent mechanical and corrosion properties at relatively high temperatures (650°C).
This literature review examines the current state of the art in regards to post-built heat treatment of material produced through Laser Powder Bed Fusion. The detailed parameters used for the treatments have been extracted and summarised. The effect of the treatments on the microstructural properties is discussed specifically, in the context of decreasing the anisotropic nature of the microstructure in the as-built condition. Similarly, the resultant mechanical properties are summarised and discussed.
Key Findings
- Current research has focused on replicating current heat treatment standards.
- Current heat treatment temperatures are not sufficient to remove detrimental phases from the microstructure.
- Increasing the heat treatment temperature dissolves detrimental phases and leads to grain growth, decreasing anisotropy.