Abstract: This study proposes a low-energy pulse current (LEPC) rapid solution treatment method, which can dissolve more primary γ′ phase in a shorter time and effectively suppress abnormal grain growth, thereby successfully achieving microstructure optimization and property enhancement. The microstructure analysis showed that, compared with the 62.5 % dissolution rate of the standard traditional solution treatment (1100 ℃/4 h), LEPC achieved an 88.9 % dissolution of the primary γ′ phase in just 5 min at the same temperature. Furthermore, due to the rapidity of the LEPC treatment and its “targeted dissolution effect” on the γ′ phase, excessive grain growth was effectively suppressed, resulting in grain size comparable to those obtained with traditional solution treatment. Mechanical property testing indicated that the alloy treated with LEPC had a hardness of 531 HV at room temperature, while the yield strength, Ultimate strength, and maximum strain reached 994 MPa, 1030 MPa, and 5.1 % at the service temperature (750 °C). Compared to the standard traditional solution treatment, these properties were improved by 10.4 %, 11.1 %, 10.4 %, and 17.5 %, respectively. Finally, theoretical calculations revealed that the non-thermal effect of LEPC reduced the dissolution-free energy by approximately 49.4 kJ/mol and increased the diffusion coefficient by about 76 times, which was the fundamental reason for the accelerated dissolution of the primary γ' phase.

Key words: Low-energy pulse current, Solution treatment, Primary γ′ phase, Targeted dissolution effect, Microstructure, Property