Synergistic enhancement of hot corrosion resistance and mechanical properties of IN738LC alloy prepared by selective laser melting

Abstract

The present study investigates the synergistic enhancement of hot corrosion resistance (900 °C, 75%Na2SO4+25%NaCl) and mechanical properties of IN738LC alloy prepared by selective laser melting after heat treatment. The results indicate that the M23C6 precipitation at the grain boundaries coupled with smaller-sized γ′ phase distribution in the inner grain is conducive to the formation of thicker Cr2O3 outer layer and Al2O3 inner layer for the samples, which effectively hinders the diffusion of S and Cl elements penetrate to the matrix, enhancing the hot corrosion resistance. Additionally, the presence of small-sized γ′ phase and re-crystallization-induced grain refinement contribute to an increase in yield strength (σYS = 1261 MPa) and ultimate tensile strength (σUTS = 1360 MPa) for the alloy.

Keywords

• Selective laser melting (SLM)
• IN738LC alloy
• Heat treatment
• Hot corrosion
• Mechanical properties