Data for 1. Yu, Z., Zhang, C., Voyles, P. M., He, L., Liu, X., Nygren, K. & Couet, A. Microstructure and microchemistry study of irradiation-induced precipitates in proton irradiated ZrNb alloys. Acta Mater. 178, 228–240 (2019). DOI: 10.1016/j.actamat.2019.08.012. Nb precipitates are formed in a Zr matrix by proton irradiation. This data set contains Z-contrast STEM imaging and 4D STEM strain mapping of the Nb precipitates. MATLAB scripts for strain mapping from 4D STEM data with mixed crystal references are also included.