TY JOUR TI ASSESSMENT OF THE INFLUENCE OF MACHINING MODES ON THE SURFACE ROUGHNESS OF IMPLANTS MADE OF ULTRAFINE-GRAIN AND COARSE-GRAIN TITANIUM KW titanium KW ultrafine-grain materials KW cutting KW roughness KW surface KW machining KW implants JO Transport engineering AU Khabarova4, A.V. AU Pesin, M.V. AU Makarov, V.F. AU Konogorova3, L.V. PY 2026 IS 2026 PB Bryansk State Technical University