A study on the microstructural evolution of a Ni-base superalloy (Allvac 718plus) was conducted to better understand how solutionizing temperature affects the final microstructure of solutionized and aged test samples. Four different solutionizing temperatures were used to obtain different fractions of gamma prime (γ’) and delta (δ) phase precipitates. This paper describes the solutionizing treatments and presents and analyzes the results of SE-SEM, EBSD, EDS, and XRD testing.