Influence of heat treatment on organization and properties of a novel selective zone laser melting nickel-based high-temperature alloy

The study focuses on the nickel-based superalloy ZGH451 manufactured by additive manufacturing， conducting heat treatment experiments with different processes. By analyzing the microstructure and mechanical properties， an optimized heat treatment regime suitable for this alloy has been developed， which consists of short-time high-temperature solution treatment followed by two-stage aging. The results indicate that the optimal heat treatment process is as follows： 1250 ℃ for 15 min （air cooling） + 1100 ℃ for 4 h （air cooling） + 850 ℃ for 24 h （air cooling）. After complete heat treatment， the element segregation within the alloy is eliminated， resulting in a γ' phase microstructure with favorable size （436 nm）， area fraction （63.74%）， and cubic morphology. Additionally， the tensile properties at 760 ℃ are significantly improved， with a tensile strength of 1142 MPa and an elongation of 22.8%.