||This study establishes the temperature model and plastic flow model of the workpiece during the welding process of the friction stir welding spot welding titanium alloy (Ti-6Al-4V) and aluminum alloy (AA6061-T6) using the an Embedded-rod tool, and then compares with the experimental results and fix the model. The effects of different rotational speeds, downward force and dwell times on the temperature and the depth of the plastic flow layer of the workpiece material were discussed. This study also explored the friction stir welding of commercial grade pure titanium (CP Ti) to aluminum alloy (AA6061-T6).|
The results show that when the interface temperature of the two plates rose to about 730 ° C ~ 750 ° C, the molten aluminum alloy has a great chance of breaking through titanium alloy upper plate, and before that , the measured value of the downward force will be greater than the set value of about 0 ~ 0.5 kN. The greater the downward force and the rotational speed, the faster the rate of temperature rise, but The effect on the temperature when the aluminum alloy breaking through the titanium alloy was not obvious. Under the operating parameters of 12 kN 1200 rpm, the time for the aluminum alloy to break through the titanium alloy is about 15~17 seconds. The boundary between the fusion zone (FZ) and the heat affected zone (HAZ) of the aluminum alloy can be observed through its macrostructure and microstructure, which is consistent with the numerical model. In the friction stir point welding process of pure titanium to aluminum alloy, the plunge depth is greatly increased, and the welding tool penetrates the pure titanium upper plate in a few seconds. The greater the downward force, the greater the plunge depth, and the greater the rotational speed, the earlier plunge depth begins to rise.