| The high strength aluminum alloy of 7A52 is researched by China,which is often existed as welding structure in the actual engineering application.The properties of traditional welding joint were seriously affected by weld porosity or low strength.In recent years,the rapid development of laser welding technology is expected to solve the series of welding problem.In this paper,6mm-thick 7A52 aluminum alloy is studied by using YLS-6000 fiber laser welding,which is made by IPG company.The form of the joint is butt joint.The effect of laser power,welding speed and focal parameter on tensile strength have been studied in the experiment by design of orthogonal experiment and the optimal process condition was recommended by the range analysis.The sequence of parameters of fiber laser welding which effects of tensile strength welding joint is Rc>Ra>Rb.And the optimal parameters of the6mm-thick 7A52 aluminum alloy welding joint is welding power 5.2kW,welding speed40mm/s and focal distances 0mm.The tensile strength of welding joint under the optimal parameter is 336 MPaand the strength coefficient attach to 69.7%,the fracture of the welding joint is a mixed ductile-brittle fracture.The single-aging study of welded joint found that bases metal micro-hardness changed in accordance with welded micro-hardness at the aging temperature of 120??140? and 160?.The influence of joint age hardening process of aging temperature is quite remarkable.The age hardening rate of joint was noticeably increased and the peak hardness time was reduced with increasing aging temperature.When aging 16 h at 140?,the welded joint performance is better.The precipitate phase of the welding joint and the base metal was MgZn2 and the main strengthening phase were ?,phase and GP zone at peak aging state. |
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