焊接参数对搅拌摩擦焊接质量的影响

采用基于固体力学的有限元方法建立了搅拌摩擦焊接过程的三维数值模型，研究了在焊接参数不同的情况下搅拌摩擦焊接过程中力学特征的变化．数值模拟结果和试验结果都表明，等效塑性应变能近似地反映焊接构件焊缝区域材料显微结构的演化，较高的搅拌头转速和较低的焊速有利于提高焊缝的质量．焊接构件特定的等效塑性应变等值线可以较好的对应不同焊接区域的边界．随着搅拌头转速的提高，等效塑性应变随之增大，但搅拌探针与焊接构件交界面上的接触压力随之减小．等效塑性应变随着搅拌头平移速度的增大而减小．

Effect of process parameters on quality of friction stir welds

Finite element method based solid mechanics is used to establish a three dimensional model of friction stir welding process. The effect of the variations of process parameters on the mechanical features in friction stir welding is studied. The comparisons of numerical results and experimental ones show that the equivalent plastic strain can approximately correlate with the microstructural evolution. It can be found from both the numerical model and the experiments that the friction stir weld can be improved when the angular velocity of the pin is increased or the welding speed is decreased. The distributions of the equivalent plastic strain can correlate with the boundaries of the microstructure zones. With the increase of the angular velocity of the pin, the equivalent plastic strain is increased. However, the contact pressure on the pin-plate interface is decreased with the increase of the angular velocity of the pin. The equivalent plastic strain is decreased with the increase of the translational velocity of the pin.