Numerical simulation of linear friction welding of titanium alloy: Effects of processing parameters

摘要

Numerical modeling of linear friction welding (LFW) of TC4 titanium alloy was conducted using ABAQUS/ Explicit with a 2D model. The coupled thermo-mechanical analysis was performed with the Johnson-Cook material model. The effects of processing parameters on the temperature evolution and axial shortening of LFW joints were numerically investigated. It is shown that the temperature at the interface can first increase quickly to about 1000 ℃ within 1 s, then increases slowly, and finally tends to become uniform across the interface under certain processing conditions. The temperature gradient across the joint from the interface is very high during the friction process. Consequently, significant axial shortening and fast formation of flash start to happen as the interface temperature becomes more uniform. During cooling, the interface temperature decreases steeply at a rate of several hundred degrees per second because of the fast heat conduction to the cold end of the specimen. The temperature distribution appears to be uniform in the joint after about 30 s. At a higher oscillation frequency, the interface temperature rises more quickly and the axial dimension shortens more and at a faster rate. The same phenomena are observed for the amplitude and friction pressure. The effects of these three factors can be integrated into one parameter of heat input. The axial shortening increases with increasing heat input almost linearly as the heat input exceeds a critical value.