Shape And Tissue Control Of Aluminum Alloy Spray Deposition

Hypereutectic Al-Si alloy is the most common cast aluminum, which has a low thermal expansion coefficient, high wear resistance and anti-seize property. It has been widely used in many kinds of piston members. However, when hypereutectic Al-Si alloy was prepared by conventional cast, thick strips or bulk primary silicon appear. The primary silicon not only seriously fragments the continuity of the matrix, but also increases brittleness, and causes difficult cutting, which limits the widespread application of hypereutectic Al-Si alloy. The refinement of hypereutectic Al-Si alloy primary silicon has become very popular among researchers.The laboratory prepared hypereutectic Al-Si alloys by spray deposition, and the deposition billet was dandified by the technology of continuous extrusion.The Spray conform technology is these two processes together. Author discusses the matching of spray deposition technology and continuous extrusion technology. By improved, designed the flow controller, to control the deposition area and the blank to complete the match continuous extrusion of spray deposition.Specific studies following points:(1) Based on the shortcoming of V-baffle Flow Controller-Dual Roller Flow Controller-Senior Roller Flow Controller-a small four-roll flow controller, designed the axle plate type flow controller and dual rotating disc flow controller.(2) It was found that the double rotating disk flow controllers to obtain the width of 10-12mm deposition billet. The deposition billet quality is better.(3) Explore the spray deposition continuous extrusion process, the basic parameters of spray deposition. Contrast deposition billet morphology, microscopic size and finally arrive at more appropriate parameters. The appropriate parameters is Ⅲ number using a nozzle,pressure of 0.3MPa, superheat is 180 ℃-200 ℃, Double speed≥1000r/min, spray distance of 294mm, Double angle≤10 °.(4) Al-20Si was performed by spray Conform method with twin rotating disk flow controller, the microstructure of the material was greatly refined, the equivalent diameter of primary Si was 3.4μm, sphericity 1.2 and dispersion factor was 2.3 μm. The tensile strength reaches 204MPa, elongation is greater than10%.