Abstract In this study, the effect of solution heat treatments on the microstructure and mechanical properties of Inconel 625 superalloy fabricated by laser solid forming was investigated. The microstructure of deposit was mainly composed of columnar grains, which didn't change until the solution temperature reached 1200 °C after solution heat treatment. Due to the large size Laves phase which can pin grain boundary and obstruct grain boundary migration, the recrystallization fully occurred when the solution temperature exceeded 1200 °C. With the increment of the solution temperature, the average diffusion coefficient of solute elements and the dissolution velocity increased obviously. Besides, the volume fraction and size of Laves phase decreased, and the dislocation density decreased apparently. As a result, the microhardness and yield strength decreased with the increment of the solution temperature, but the tensile strength didn't change much after solution heat treatment, and the elongation increased significantly with the solution temperature improving. The room-temperature tensile properties in different states of Inconel 625 fabricated by laser solid forming were higher than those of Inconel 625 fabricated by casting.

中文翻译：

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固溶热处理对激光固体成形Inconel 625高温合金组织和力学性能的影响

摘要 本研究研究了固溶热处理对激光固体成形Inconel 625高温合金组织和力学性能的影响。沉积物的显微组织主要由柱状晶粒组成，固溶热处理后直到固溶温度达到1200℃才发生变化。由于大尺寸的 Laves 相可以钉住晶界并阻碍晶界迁移，当固溶温度超过 1200 ℃时，再结晶完全发生。随着溶液温度的升高，溶质元素的平均扩散系数和溶解速度明显增加。此外，Laves相的体积分数和尺寸减小，位错密度明显降低。因此，显微硬度和屈服强度随固溶温度升高而降低，但固溶热处理后抗拉强度变化不大，伸长率随固溶温度升高而显着增加。激光固体成形Inconel 625在不同状态下的室温拉伸性能高于铸造Inconel 625。