Numerical Simulation Of The Influence Of Nano-powders On Solidification Structures Of Al Alloy

Due to excellent properties,aluminum alloy was widely used.The researchers continuously improve the performance of aluminum alloy to meet the various environments.Therefore,on the basis of previous studies,the research added TiC and TiB2 nano-powders into Al-11.2%Cu melt,then analyzed the effect of TiC and TiB2 nano-powders on solidification structure of Al-11.2%Cu.On this basis,it was simulated that solidification structure was added TiC and TiB2 nano-powders and changed the external conditions by CAFE model of ProCAST software.And the effects of TiC and TiB2 nano-powders on the solidification structure of Al-11.2%Cu were analyzed and discussed.Firstly,this paper simulated solidification structure of Al-11.2%Cu with and without TiC and TiB2 nano-powder by ProCAST software and gained nucleation parameters combined with experimental solidification structure.Then the research calculated the absorptivity rate of TiC and TiB2 nano-powder as heterogeneous nucleation core in Al-11.2%Cu.The results showed that:when particle size is at 0.01?1?m,the absorptivity rate decreased with the increase of the particle size of TiC and TiB2 nano-powder.Therefore,it was more reasonable to select the smaller particle size of TiC and TiB2 nano-powder,when adding TiC and TiB2 nano-powder into Al-11.2%Cu as the core of heterogeneous nucleation.Secondly,solidification structure of Al-11.2%Cu simulated by ProCAST software when amount of TiC and TiB2 nano-powder were 0%,0.1%,0.3%?0.4%?0.5%.The results showed that:the solidification structure of Al-11.2%Cu was diversely refined with the increase of the amount of TiC and TiB2 nano-powder,but the average grain size is in the same size class,and the decrease amplitude became weak.Therefore,it was more reasonable to select the mass fraction of 0.1%as the amount of TiC and TiB2nano-powder.Thirdly,designed orthogonal simulation scheme by changing undercooling,pouring temperature,mould temperature.Then,solidification structure was simulated under condition of different plan.It turned out that:the optimum technological parameters with TiC nano-powder was undercooling of 5K,mould temperature of 110 ?,pouring temperature of 760?;the optimum technological parameters with TiB2 nano-powder was undercooling of 5K,mould temperature of 110?,pouring temperature of 800?.Lastly,in this paper,TiC and TiB2 nano-powders were modified and their surface activity was larger.So when they were added into Al-11.2%Cu and were apt to exist in the Al-11.2%Cu melt.TiC and TiB2 nano-powders in Al-11.2%Cu alloy exist in the form of heterogeneous nucleation and nanoscale cold iron.