Solid-liquid Composite Casting Technology Of Hypereutectic And Hypoeutectic Al-Si Alloy

With the pace of the 21 st century,the world of science and technology and industrial production has been rapid breakthrough and development.The cylinder sleeve,made by a eutectic aluminum silicon alloy,can realize the preparation of "whole aluminum engine",which is helpful to improve the efficiency of the engine,prolong service life,etc.It plays an important role in the development of automobile industry,environmental protection and energy saving.At present,countries across the eutectic aluminum silicon alloy cylinder sleeve material research relatively mature,and constantly strengthen the cylinder liner/cylinder assembly technology research and development,but each method is relatively complicated,and there are some problems.Because of imbedding technology method is simple,not the solid with casting size,shape,size and material requirements,such as widely used,in this paper,in order to better close to the actual production,with minimal cost and resources to achieve optimal metallurgical combination,adopt the method of sand mold casting,gravity casting,through the aluminum/aluminum solid-liquid bimetallic composite molding process of experiment,the surface treatment of aluminum/aluminum solid-liquid bimetallic composite molding process,the influence of the rough surface treatment,smooth grinding processing,electric galvanized,nickel plating processing,plating copper processing the impact on the composite interface and organization;In electroplating copper,for example,in order to investigate the influence of cathode current density of electrodeposited coating and plating time and plating thickness,the relationship between research and pouring temperature,preheating temperature,plating time on the influence of the double metal composite forming interface.Through the study of this article,the main results are follows:(1)It was found that the surface roughness,smooth processing can not make aluminum/aluminum solid-liquid bimetallic reach metallurgical combination,its basic reason is the interface of the oxide layer of bimetal wetting,and in the process of casting aluminum alloy preform surface secondary oxidation,causing poor interface combination.(2)It was found that electric galvanized,nickel,copper processing helps the solid-liquid bimetallic metallurgical combination,zinc,nickel,copper element on both sides of the interface diffusion,nickel,copper,have gathered phenomenon occurred in the diffusion process.15 min in pouring temperature 750?,electroplating,preheating temperature is 100 ?condition,the copper plating process after casting the shear strength of up to 23.45 MPa,copper diffusion distance is about 400 um.(3)It was found that current density of 5A/dm2 as the best current density,copper plating layer,burr and bubble surface level off good,electricity between coating and substrate quality accord with standard of plating deposit.When electroplating time respectively is 5min,10 min,15min,get the actual copper plating thickness,respectively is 6.46 um,8.18 um,10.24 um.(4)It was found that in the pouring temperature is 780?,the plating time is 10 min,preheating temperature of 100 condition,can get the largest bimetal composite in? terface shear strength is 28.23 MPa,the influence of various parameters on the interface combination of pouring temperature is the main sequence,plating time,preheating temperature.The comprehensive consideration,think the pouring temperature is 750?,electroplating time for 15 min,preheating temperature is 100?,as the best technological parameters.