| Title |
Effects of Nb Content and Heat Treatment on Microstructures and Mechanical Properties of Alloy 718 |
| Authors |
안형준(Hyung Joon Ahn); 신평우(Pyung Woo Shin); 최병학(Byung Hak Choe); 박노광(Nho Kwang Park) |
| Abstract |
Segregation of Nb during solidification results in the formation of Laves phase in the interdendritic regions of cast Alloy 718. The Laves phase can be dissolved in the matrix by suitable heat treatments. In the present study, the effect of Nb content and homogenization treatment on tensile properties and hardness was studied at room temperature. Nb content was varied within 5.2∼6.2wt.% Nb. Homogenization treatments were conducted on as-cast alloys at 1100℃/1hr, 1100℃/10hr, 1200℃/1hr and 1200℃/10hr. The hardness increases with increasing Nb content to a different extent depending on homogenization treatment. Tensile properties vary with Nb content and homogenization treatment in a complex way. The effects of Nb content and homogenization on mechanical properties are attributed to the combined effects of Laves dissolution and γ´/γ˝ precipitation. |