Centrifugal Casting Hypereutectic Al-Si Alloy Particle Distribution Gradient Sudden Cylinder Liners Composite Materials Technology And Properties

The particle-reinforced metal matrix composites (PMMCs) has specific strength and stiffness and superior wear resistance, so many researchers and engineeres have focused on research of the fabrication and forming process of composites。This paper studies the centrifugal casting hypereutectic aluminum-silicon alloy cylinder-shaped pieces of the casting process, Prepared Al which primary crystal Si and the Mg₂Si pellet mix strengthened the base to change suddenly the gradient compound materials.Analysis the organization, the components and the performance of material. The experimental mainly take the Al-19Si-5Mg alloy as a matrix. Uses the metal mold centrifugal casting,Casting hyper-eutectic aluminum silicon alloy pellet sudden change distribution gradient compound materials tube shape components, so that the formation the interior for primary crystal Si and Mg₂Si the pellet enhancement level, the outside for the non-enhancement level graded distribution of the tubular piece.The experiment in the pour into centrifugal mold craft aspect to the centrifugal rotational speed, the mold temperature, the pouring temperature has carried on the contrast. Through uses 4 kind of different centrifugal rotational speeds (450r/min,600r/min,800r/min,2000r/min),May discoberd, the more rotational speed is quicker, the more primary crystal Si and the Mg₂Si pellet gathers the degree to be higher, the enhancement level is more compact, and thickness is thinner, Therefore time 2000r/min the tube shape components gather the effect to be best. Therefore 2000r/min is the best the tubulat piece components gather. Has contrasted the high mold temperature and the low mold temperature conditions, may discover that the mold temperature is higher, so the pellet gathers is fuller and gathers the effect to be more obvious. Then contrasts the different pouring temperature, It discovery pouring temperature for 660℃, the tubular piece's flaw are least and the quality is best.Regarding casting defect of the tubular piece components, it has analysis and discussion from the casting way and the casting speed two aspects to the tubular piece components blow hole and the shrink hole formation reason. Finally it has determined the ideal casting condition.Analysis the pellet stress and movement relations through the centrifugal field. Advance mix gathers the mechanism about primary crystal Si and the Mg₂Si enhancement pellets. The Mg₂Si pellet has higher centripetal velocity of movement than the primary crystal Si pellet. Under the centrifugal force function, the quick Mg₂Si pellet and slow primary crystal Si has collision. It has the Mg₂Si pellet to adhere and to wrap the primary crystal Si pellet, and impels the primary crystal Si pellet together to the components interior movement, thus forms the sudden change gradient function compound materials which the mix strengthens.The formed tubular piece used T6 of the heat treatment way, The contrast examined resistance to wear-resisting property, hardness and erichsen property in the solution treatment ,the aging treatment and cast condition. May discover that the wear-resisting property result follows the aging treatment surpass the metal casting result, the metal casting result surpasses the solid solution treatment result.After aging treatment of metal, strengthens the level the wearing capacity is 0.009g obviously surpasses the non-enhancement level wearing capacity.The hardness of material, under three conditions, degree of hardness value is highest after solution treatment, the degree of hardness value about enhancement level's is equally HRB90, the aging treatment is better, the cast condition condition is worst.The solution treatment is 206.856MPa in the erichsen of material under three different conditions, the next is the aging treatment of metal and the cast condition is lowest.The solution treatment highest is 1.155% in the elongation ratio, the aging treatment of metal is higher and the cast condition is lowest.Through used the centrifugal casting process to complete had the gradient change compound materials tubular piece components preparation.The result indicates the reasonable adjustment foundry technique parameter, the adjustment compound materials setting time and the formed components coagulation order. Through to the compound materials design, the material preparation and formed basic research indicated make the gradient compound materials cylinder preparation is feasible. This research indicated that grasps the material preparation and the forming process rule, discusses the material preparation and the forming process material organization lift-drag ratio relations thoroughly, it might the effective instruction actual product development.