The Microstructure And Property Of Research About Semi-Solid Of Hypereutectic Al-Si Alloy By Slope Method

The traditional process of the preparation of bubble metallurgy of hypereutectic al-si alloy ,because of its organization with bulky polygons in primary crystal silicons, lead to base structure of separate and polygon silicon phase structure form stress midpoint pointed horn, make the mechanical properties of the alloy low, cannot play its low inflation and high wear-resisting performance potential in order to limit its application. Semi-solid forming technology through semi-solid blocking and extrusion forming technology, primary crystal silicons can be refined, And primary crystal silicons polygon pointed horn of spherical, can achieve the purpose of improving alloy performance.In this project, slope cooling process preparation semi-solid casting pieces on microstructure and properties and the influence of the research work carried out.This subject introduces a design slope cooling device system, the slope cooling process half-and-half solid billet pieces of the influence of the organization. make sure the suitable for semi-solid aluminum alloy cooling process parameters of blocking slope Using alloy strengthening principle designed a kind of hypereutectic al-si alloy, the bad treatment secondary heating rheological and touch into shape technology and alloy organization and performance relationship, and make the heat treatment of alloy.The project by Extensive Experimental Studies, get process parameters Eventually include: The optimal semisolid alloy blank parameters: Tilt board length: 650 mm;Tilt board slope Angle: 45°Tilt board pouring temperature: 600℃-625℃; The optimal parameters of reheating:Φ10mm×15mmcylindrical specimens: Heat preservation temperature: 585℃; Holding time: 20-30 min,Φ80×70mm billet pounds Heat preservation temperature: 595℃; Holding time:120min; Extrusion parameters: Extrusion head extrusion trip: 125 mm; The filling speed: 2mm/s; The holding time:60s; Mould heating temperature: 500,semi-solid forming tensile strength reach 227.04MPa,rigidity HB121,elongation 1.78%,after heat treatment tensile strength reached 264.35MPa,than as-cast improved 123.3%.Experiment results show: the semi-solid blocking alloy by slope method,α-Al Matrix spheroidizing and homogenization; after semi-solid forming, eutectic silicon phase with Bulky needle flake disappeared, Sharp-angled passivation and roundness , formation of granular or short clavite phase, huge primary silicon phase being broken and eliminated. After heat treatment,shape and size of eutectic silicon phase change prominently, become more roundness,wee,uniformity.