The influence of Si content on precipitation behavior and high-temperature mechanical stability in ERNiMo-2 deposited metal.

Microalloying is an effective method to regulate the mechanical properties of deposited metal. In this paper, ERNiMo-2 deposited metals with different Si content were prepared. The influence of Si element and thermal exposure treatment on microstructure evolution and high-temperature mechanical properties of ERNiMo-2 deposited metal was investigated. The results show that the size and distribution density of eutectic carbides increased significantly with the addition of Si while more M2C nano-sized carbide particles were observed around the eutectic carbide. Thermal exposure treatment hardly influence the size and distribution of the eutectic carbides, but significantly promote the formation of nano-sized carbide particles. The tensile results at 700 °C show that the density of precipitated carbides and the yield strength of deposited metal increased significantly with the increase of Si content. The thermal exposure would soften the deposited metal because of the obvious decrease of dislocation density and the unobvious strengthening effect from nano-sized carbide particles. The research results are significant for optimizing the composition of ERNiMo-2 welding wire and improving the mechanical performance of welded components. [ABSTRACT FROM AUTHOR]