티타늄 레이저 용접부의 기계적 성질 평가 = Mechanical Properties of Laser-Welded Titanium Joints

다국어 초록 (Multilingual Abstract)

This study was performed to examine the effects of laser output energy on the mechanical properties of laser-welded titanium joints. Titanium rods of 3 ㎜ in diameter were perpendicularly cut to 30 ㎜ in length for the laser welding. Two rods were fixed to each other with a jig and welded vertically using a Nd:YAG laser at output current of 210-270 A. The penetration depth of the laser beam against the titanium was measured with the changes of output current, pulse duration, and spot diameter. Mechanical tests included tensile testing and Vickers microhardness of the joints. Tensile testing was performed at the crosshead 00speed of 1.0 ㎜/min and a gauge length of 30 ㎜ with a universal testing machine. Vickers microhardness was mesured under 9.8 N load for 15 seconds. The results obtained were summarized as follows; With increasing the output current, the penetration depth of the laser to titanium was increased. Tensile strength values of laser-welded groups were the relatively higher than that of non-welded parent material group. There were significant differences in tensile strength between the specimens of laser-welded at output currents 250 A, 270 A and non-welded parent material group(p<0.05). Microhardness values were increased in the heat-affected zone. Brittle fracture regions were observed in the specimens of laser-welded at output currents 270 A.