6082铝合金激光填丝焊热影响区的软化现象

The laser welding of 6082 Al alloys with filler wire is conducted and the influence of the welding speed on the softening of the heat-affected zone (HAZ) of the welding joints is investigated. The results show that, the obvious dissolution of β" reinforced phases in the HAZ occurs when the temperature is between 430℃ and 560℃. The number of β" phases decreases substantially and thus the hardness and the tensile strength of these joints decrease. This deep softening effect of the HAZ occurs and the softening area of the HAZ becomes the weakest one of these joints. At a laser power of 4250 W and a welding speed of 2.7 m•min^-1, the local deep softening phenomenon of the HAZ can be effectively suppressed. The average hardness is larger than 82 HV, the tensile strength increases up to 249 MPa, and the tensile fractures occur in welds.