聚碳酸酯激光透射焊接力学性能分析

Mechanical properties of laser transmission welding of polycarbonate

为研究聚碳酸酯激光透射焊接力学性能,采用10 W半导体端泵浦全固态激光器进行了透明与不透明聚碳酸酯的焊接.采用光学金相显微镜(OM)、场发射扫描电子显微镜(SEM)、显微硬度仪和电子万能实验拉力机分析测试了接头的显微形貌、断口形貌、显微硬度分布及拉伸抗剪强度.结果表明,随着激光面能量的增加,接头的连接形式由焊接接头演化为类似粘接接头;分层和气孔是影响接头力学性能的主要原因,通过控制面能量,可获得力学性能良好的焊接试样,在面能量为0.23 J/mm2时,拉伸抗剪强度达到44 MPa,约为母材强度的68%,且接头的显微硬度与母材相当;接头的断裂机制为混合断裂机制.

In order to analyze the mechanical properties of laser transmission welding of polycarbonate,the transparent and opaque polycarbonates were welded by a 10 W diode end pumped solid state laser,respectively.The microstructure,fracture appearance,micro-hardness and tensile-shear strength of the welded joint were tested by optical metallographic microscope(OM),field emission scanning electron microscope(SEM),micro-hardness tester and electronic universal tensile machine,respectively.The results showed that the joint gradually become as similar adhesive joint from welded joint with the increase of laser power density.Layering and pores in the welded joint are the defects to resulting in poor mechanical properties.The mechanical properties of the welded joint can be improved by controlling laser power density.At the laser power density of 0.23 J / mm2,the tensile-shear stresses reaches 44 MPa,which is 68% of that of the basic materials.The micro-hardness on the center of the welded joint is very close to the basic material.The fracture is the mixture of ductile fracture and brittle fracture.