Effect of Heat Treatment and Transformation on Bending Angle in Laser Forming of Titanium Foils

摘要

Pure titanium foils were bent by laser forming and the effect of α-β transformation and history of heat treatment of specimen on bending angle was investigated. The thickness of specimens was changed from 40 to 100μm, the length of them was 20mm and the width of them was 10mm. The specimens were annealed at 600-1100℃ for 30 minutes in argon atmosphere. A 20W YVO_4 laser was employed and laser power was changed from 2 to 16W. From the experimental results, when laser power was increased, bending angle also increased and it was dramatically changed at the laser powers occurring α-β transformation and melting. Bending angle increased as grain size increased and it jumped up when grain size exceeded the foil thickness and then became constant. Bending angle decreased by annealing after forming and degree of decrease was greater when the annealing temperature before forming was lower.