Powder-enhanced friction stir rivet welding device and method

A powder-enhanced friction stir rivet welding method, comprising:

• (1) fastening an upper sheet and a lower sheet by clamping followed by stacking on a tooling mould;
• matching a rivet with a shoulder of a hollow spindle followed by placing on a point to be riveted and welded;
• applying a pre-tightening force to the rivet and the point to be riveted and welded through the hollow spindle;
• transporting a reinforced powder in a reinforced powder bin and a base material powder in a base material powder bin into a cavity of the hollow spindle through a pipeline by using a powder feeding pump;
• and at the same time, mixing the reinforced powder with the base material powder in the cavity of the hollow spindle through vertical vibration or rotation of a mixing screw rod to obtain a mixed powder;
• (2) allowing a rotor of a first servo motor to drive the hollow spindle to rotate, such that the rivet performs local friction preheating on the point to be riveted and welded, wherein the first servo motor is a hollow-shaft servo motor;
• (3) keeping the rotor of the first servo motor rotating;
• driving, by a second servo motor, a hollow ball screw to move downwards, so that the rivet under rotation is inserted into the upper sheet;
• injecting the mixed powder through a central through hole of the rivet;
• and fully mixing the mixed powder and a metal material at the point to be riveted and welded under friction stir of the rivet, such that the mixed powder and the metal material at the point to be riveted and welded are plasticized under an action of friction heat;
• (4) allowing the rivet to continuously move downwards until a shoulder of the rivet is inserted into the upper sheet;
• applying, by the second servo motor, an upsetting force to the rivet;
• allowing the rivet to continuously rotate to perform friction stir on the point to be riveted and welded for 5-20 seconds through the rivet and the shoulder of the rivet;
• stopping rotation of a first servo motor after the mixed powder and the metal material at the point to be riveted and welded are fully extruded and mixed;
• and naturally cooling the metal material to enable the metal material to solidify with the rivet to obtain a rivet welding joint, so as to realize powder-enhanced friction stir rivet welding of the upper sheet and the lower sheet;
• and
• (5) after the point to be riveted and welded is cooled and solidified, driving, by the second servo motor, the hollow ball screw to move upwards, so as to drive the hollow spindle to retract to an initial position and finish a friction stir rivet welding process.