Precipitate strengthened high-temperature alloys are currently used in safety-critical applications. Understanding precipitate stability and solute segregation mechanisms at high temperatures is key to designing high-strength alloys. Rapid

in-situ

approaches

therefore

are pivotal in accelerating the alloy design process. Hereby using the test case of a promising high-temperature Al-Cu-Mn-Zr alloy

we demonstrate the value of

in-situ

atom probe tomography coupled with

in-situ

transmission electron microscopy to reveal atomic-scale mechanisms that lead to the emergence of non-equilibrium solute segregation. Mn and Zr segregation at strengthening precipitate(

θ’)

-matrix interface increases the kinetic barrier for phase transformation thus retaining high-temperature strength.