Modeling, impact evaluation, and optimization of machining performances of heat-treated SKD61 steel in a tungsten powder alloy mixed EDM process via the RSM-GRA methodology - Le, Van-Tao; Banh, Tien Long; Nguyen, Thi Hong Minh; Hoang, Tien Dung; Dang, Van Thuc; Phan, Hoang Cuong (VNUHCM Journal of Science and Technology Development, 2023)