Peculiarities of High-Energy Thermal Effect on Structure and Properties of Surface Layers of Titanium Alloys During Plasma Cutting

The results of a study of the surface morphology and structural features of near-surface layers of titanium alloy samples of Grade2 and Ti-2Al-1.5Mn during plasma cutting are presented. The study reveals the formation of martensitic structures with a hardness considerably exceeding that of the base metal in the near-surface volumes of the samples. The Ti-2Al-1.5Mn alloy samples are characterized by relatively low surface oxidation, while the samples of Grade2 alloy are characterized by the formation of oxide layers with a hardness of up to 10–17 GPa. The cut zone structure depends largely on the cutting current and the corresponding values of the heat input. The bottom part of the cut is much less homogeneous than the top part, especially in the cases where the samples are stacked. Cutting with an initially insufficient heat input leads to the formation of beading in the bottom part of the samples or to significant disturbances in the macrogeometry of the cut.