Nickel-based superalloy Nimonic 80A modified with various Al and Ti contents has been developed. The gamma' coherently precipitates in the gamma matrix on {100}gamma/gamma and {110}gamma'/gamma atomic planes. The volume fraction of gamma' increases significantly with the increase of Al and Ti contents. But the volume fraction of gamma' decreases after stress-rupture tests compared with that after full heat treatment, which is primarily due to the coarsening of gamma' and the increased width of gamma matrix channel. The strengthening effect of Ti is more significant than that of Al at room temperature. While the strengthening effect of Al is more significant than that of Ti at 750 degrees C/310 MPa. The increased volume fraction of gamma' leads to the increased room temperature tensile strength and stress-rupture life at 750 degrees C/310 MPa. However, the eta-Ni3Ti is identified after full heat treatment in the alloys when the Ti content is about 2.7 wt.%, which results in decreased stress-rupture life. But the precipitate of eta-Ni3Ti does no harm to the room temperature tensile properties. (C) 2012 Elsevier B.V. All rights reserved.