Effect of Mo Content on Microstructure and Mechanical Properties of Laser Melting Deposited Inconel 690 Alloy

Abstract

Inconel 690 alloy is widely used in nuclear power, petrochemical, aerospace, and other fields due to its excellent high-temperature mechanical properties and corrosion resistance. The Inconel 690 alloy with different Mo content was fabricated by laser melting deposition (LMD). The effects of Mo content on the microstructure and mechanical properties were investigated. The microstructure of as-deposited Inconel 690 is composed of columnar dendrites grown epitaxially, and M23C6 carbides are precipitated in the grain boundaries. With the increase of Mo content, the amount of precipitated carbide increases gradually. At the same time, the grain boundary becomes convoluted. The tensile test at room temperature shows that the high Mo content in the as-deposited Inconel 690 increases the ultimate strength but decreases the ductility. Compared with low Mo content, the alloy with high Mo deposition has better mechanical properties. The present study provides a new method to achieve the preparation of Inconel 690 alloy with excellent integrated mechanical properties.