材料期刊网

Compared with the conventional In718 alloy, the addition of Al at the level of 1.24% and 1.50% greatly increases the precipitation of gamma' phase and the compact form of gamma ''/gamma'/gamma '' structure, which has been demonstrated in previous studies. The delta phase precipitation at the grain boundaries is noticeably suppressed. Large amount of Laves phase ((Fe, Ni, Cr)(2)(Nb, Mo)), small amount of M(7)C(3) carbide and sigma phase ((Fe, Ni)(Cr, Mo, Nb)) are precipitated at the grain boundaries. After aging at 680 degrees C, the grain boundary precipitates are increased significantly. Large amount needle-like s phase is precipitated at the grain boundary in the alloy with 1.50% Al. After aging at 680 degrees C for 1000h, the grain boundary precipitates are worsened further, but the coarsening of the compact form gamma ''/gamma'/gamma '' is lighter than the gamma '' phase in the normal In718 alloy.