Laser powder bed fusion of high-strength and corrosion-resistant Inconel alloy 725

Abstract

The development of additive manufacturing, or three-dimensional (3D) printing, technologies has produced breakthroughs in the design and manufacturing of products by enhancing design freedom and minimising manufacturing steps. In addition, the complex, unique microstructures imparted by the additive processes offer prospects of unprecedented advances to produce high-performance metal alloys for high-temperature and corrosive environments. Here, we present the first additive manufacturing of Inconel alloy 725, an advanced nickel-base superalloy that is the widely accepted gold standard material of choice for oil and gas, chemical, and marine applications. We explore the printability of Inconel alloy 725 and identify a wide processing space to build material with a crack- and near-pore-free microstructure. The conventionally heat-treated Inconel alloy 725 has an equiaxed, near-fully recrystallised microstructure containing copious twin boundaries and nano-precipitates. It also displays promising tensile properties and corrosion resistance compared to its wrought counterpart. Our work opens the door toward additive manufacturing of Inconel alloy 725 components with optimised microstructure and topology geometry for applications in harsh environments. • We additively manufacture Inconel alloy 725, for the first time, by laser powder bed fusion. • We reveal that Inconel alloy 725 is highly printable exhibiting a wide processing window for near defect-free microstructure. • We find that Inconel alloy 725 responses well to industrial standard heat treatment compared to other common additively manufactured alloys. • We demonstrate that Inconel alloy 725 shows promising tensile properties and corrosive resistance compared to conventional wrought material.