(1) Preparation and melting of experimental alloy. According to the standard composition of 7075 alloy, the weight of various master alloys is calculated in proportion and then melted. Among them, aluminum ingot al51kg, Al Cu alloy 2.04kg, mg1.5kg, al-20mn alloy 0.45kg, al-10cr alloy 1.32kg, zn3.48kg, Al-5Ti-B alloy 1.2kg. The alloy smelting equipment is a well type resistance furnace with a loading capacity of 100kg, the smelting temperature is 750 ℃, and the refining degassing and slag stripping are kept for more than 10min.
(2) Determination of lspsf process parameters and preparation process. Semi solid slurry of 7075 aluminum alloy was prepared by lspsf process. Lspsf process equipment adopts the digital equipment controlled by the third generation PLC. The rotational speed, inclination angle and pouring temperature of the conveying pipe are set. Before the experiment, remove the impurities on the inner surface of the conveying pipe, remove the oil and water on the inner wall, preheat and brush the paint. After commissioning, adjust the inclination angle of the conveying pipe 20 ~ 35 ° and the rotation speed 90 ~ 120rpm. The deflector and the conveying pipe are fixed and preheated to 200 ℃. The slurry accumulator and tundish are preheated to 620 ℃ in a crucible resistance furnace. During pouring, the refined alloy slurry is transferred into the tundish, and a thermocouple with high sensitivity is inserted in the middle of the melt to continuously move slightly and measure the temperature. When the predetermined temperature reaches 660 ~ 680 ℃, pouring is carried out. At the outlet of the rotary tube, a slurry accumulator is used to catch the alloy slurry with low solid content, and the temperature of the slurry is measured. When the temperature of alloy slurry reaches 628 ~ 635 ℃, it is the best temperature range of semi-solid slurry. After removing the oxide scale on the surface, the subsequent parts are formed.