Investigation of absorption of laser radiation by copperand nickel-based powders to obtain gradient materials by selective laser meltingAnna Voznesenskaya, Dmitriy Kochuev, Artem Raznoschikov, Andrey Kireev and Kirill KhorkovEPJ Web Conf., 220 (2019) 03032DOI: https://doi.org/10.1051/epjconf/201922003032