Studying on the tensile mechanical properties of butt joint of 2.5mm thick TC4 welded by fiber laser,of which research method is applying synchronous infrared thermal imaging in conventional tensile experiment,real-time according the change of temperature field of specimen in tensile experiment.Conventional tensile experiment results show that the welded joint has similar strength but of which the elongation rate just reached 59.53％ of base material.The specimen temperature field test results show that:when the axial loads is below the load corresponds to the yield strength,larger yield strength area appears in the heat affected zone of welded joint,but significant plastic strain did not appear.When the load is equal to the load corresponding to yield strength,the micro plastic deformation appears before macroscopic yield point.When the load is equal to the load corresponding to tensile strength,the length of severe plastic deformation zone of joint reaches only 35％ of the base metal,and the length of severe plastic deformation zone gradually increases with the stretching process.%对光纤激光焊接2.5mm厚TC4对接接头的拉伸力学性能进行研究,其研究方法为在常规的拉伸试验中,附加同步的红外热像测量,实时记录拉伸全过程中试样在力作用下温度场的变化.常规测试结果表明:接头与母材的强度相当,延伸率只达到母材的59.53％.试样温度场测试结果表明:当接头和母材受到的轴向载荷低于屈服强度对应载荷时,接头在热影响区部位会产生较大的应力集中,但接头和母材均未产生明显的塑性变形;当载荷等于屈服强度对应载荷时,均在宏观屈服点之前发生了微观的塑性变形;当载荷等于抗拉强度对应载荷时,接头发生剧烈塑性变形区域的长度只达到母材的35％,且接头与母材发生剧烈塑性变形区域的长度随拉伸过程的进行逐渐增加.
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