Two test alloys, based on a low Nb-containing solid solution-strengthened Ni-Cr-based alloy with addition of 0.2Al+0.2Ti or 0.5Al+0.5Ti, were made by vacuum melt-casting, and then subjected to solution treatment at 1200 ^oC for 1 h and water cooling, followed by long-term aging for 10,000 h at 650 ^oC and 700 ^oC respectively. Then the effect of the Al+Ti contents on the microstructure and mechanical properties of the test alloys was investigated through thermodynamic calculations, microstructural characterization, and mechanical testing. Results show that an increase in Al+Ti content reduces the solid-liquid phase transition temperature, narrows the solidification range, and promotes the segregation of Nb and Al elements. After long-term aging treatment, the main second phase is M₂₃C₆ carbides for the 0.2Al+0.2Ti alloy, whereas for the 0.5Al+0.5Ti alloy is mainly γ′-precipitates. With the increasing exposure time, the γ′-phase undergoes significant coarsening, and its morphology transforms from cubic to rounded square. The effect of Al+Ti content on solid solution strengthening is limited, and the strength difference between the two alloys remains insignificant even after aging treatment for 10000 h, although their strengthening mechanisms differ. In the 0.2Al+0.2Ti alloy, the fine and discretely distributed M₂₃C₆ carbides effectively enhance the alloy strength during thermal exposure. In contrast, in the 0.5Al+0.5Ti alloy, the larger γ′-phase turns to split after aging for 10000 h, leading to smaller in particle size while higher in quantity and density, thereby contributing to an increase in strength.