Research On Bonding Interface Of Aluminium Alloys Cladding Materials By Semi-continuous Casting

Bimetal cladding materials have been widely used in many fields because of their excellent properties, such as engineering exploration, space industry, civil and war industry. Continuous casting is an ideal method for producing bimetal cladding materials, which can offer low production costs, low energy consumption and a simple production procedure. The critical factor about fabricating cladding ingots is the characteristics of the bonding interface between two metals. So study on the interface characteristics and analysis of heat transfer mechanism can provide guiding significance for equipment design and choosing casting parameters.In this paper,3003/4004,3003/2A11aluminium alloys cladding materials are fabricated by semi-continuous casting. The microstructures and bonding properties of interfaces are observed and investigated. In addition, the heat transfer between baffle plate and the solidification shell is studied.The principle of heat transfer in baffle plate and the feature of heat flow in the interface is summarized and analyzed. The simulated experiment results show that the heat transfer coefficient between baffle plate and solidification shell is about4200～4500W/(m2·K) and the heat transfer coefficient between baffle plate and cooling water is about40000～65000W/(m2·K). The results of heat transfer analysis are well agreed with that the practical semi-continuous casting.3003/4004cladding materials can be produced successfully by semi-continuous casting when the pouring temperature of3003and4004alloys is983K and943K respectively, the casting speed is70mm/min, the cooling water flow rate in baffle plate is250,225,200,180L/h. The good metallurgical bonding can be obtained in the interfaces and the main bonding pattern of bimetal composite material is diffused bonding. The cooling water flow rate of baffle plate has the important influence on interface bonding.when the pouring temperature of3003and2A11alloys is988K and983K respectively, the casting speed is70mm/min, the cooling water flow rate in baffle plate is200L/h,3003/2A11cladding materials can be fabricated. Mutual diffusion between main elements has taken place in the interface. α(Al)+θ(Al2Cu)+S(Al2CuMg) eutectic mixture, α(Al)+θ(Al2Cu) eutectic mixture, θ(Al2Cu) phase and a little Mg2Si phase can be observed in the interface layer. The above-mentioned results indicate the key of obtaining the metallurgical bonding interface is stable formation of semi-solid solidification shell and accurate controlling of the temperature of molten metal at the insulating side.