Abstract: Effect of solution treatment on microstructure and properties of Incoloy825 alloy was studied by means of metallographic analysis, tensile test and intergranular corrosion test. The results show that the grain size of the Incoloy825 alloy tends to increase with the increase of solution treatment temperature, but the grain growth rate is different at different solution treatment temperatures. When the solution treatment temperature exceeds 1000 ℃, the grains grow rapidly, accompanied by annealed twins. When the solution holding time is less than 30 min at 950 ℃, the mixed-sized grain structure appears in the matrix. After holding for 60 min, the mixed-sized grain state is improved, basically equiaxed grains are obtained with an average grain size of grade 7. With the increase of solution treatment temperature and the extension of holding time, the tensile strength and yield strength of the Incoloy825 alloy decrease to varying degrees, and the elongation increases. The intergranular corrosion rate of the Incoloy825 alloy decreases firstly and then stabilizes with the increase of solution treatment temperature and holding time. After solution treatment at 950 ℃ for 60 min, the corrosion rate basically stabilizes at 0.12 mm/y, and there is no significant difference in the intergranular corrosion rate with the increase of solution treatment temperature. The comprehensive effect of mechanical properties and intergranular corrosion resistance of the Incoloy825 alloy are the best after solution treatment at 950 ℃ for 60 min.

Key words: Incoloy825 alloy, solution treatment, grain size, mechanical properties, intergranular corrosion