Study On The Process Of Preparing Al-P Alloy Modified Al-18%Si Alloy By Liquid Quenching

The modification agent of Al-P alloy has been successfully prepared by casting method,and it shows a good modification effect on hypereutectic Al-Si alloy.Aiming at the problem of how to give full play to the modification effect of Al-P alloy modifier on hypereutectic Al-Si alloy,this paper takes Al-18wt%Si alloy as the research object,and uses water quenching method to prepare Al-P alloy with 0.92wt%P content to carry on the modification treatment of Al-18wt%Si alloy.Firstly,the influence of modification temperature,time and addition amount on the modification effect of Al-18wt%Si alloy was studied.On this basis,the optimal process for the modification of Al-0.92wt%P alloy was determined.Secondly,the influence of cooling rate on the modification effect and mechanical properties under the optimal modification process was studied.It is found that the minimum size of AlP in the Al-P alloy with 0.92wt%P content prepared by water quenching is less than 1?m.At the same time,it is found that large flakes of alumina are easy to form in Al-P alloy when Al-P alloy is prepared by atmospheric casting.The experimental results show that when Al-18wt%Si alloy is modified by Al-0.92wt%P alloy,the modification effect is firstly better and then worse with the increase of Al-0.92wt%P alloy,the extension of holding time after modification and the increase of modification temperature.The optimum process for the modification of Al-0.92wt%P alloy to Al-18wt%Si alloy is as follows: the modification temperature is 800?,the modification time is 5min,and the aging time is 150? for 1h,the addition amount of Al-0.92wt%P alloy is 4%.The average size of primary silicon in Al-18wt% alloy is 17.9?m after modification by the above optimal process,and the average size of primary silicon is refined by 65.9%compared with that of unmodified alloy,and the sensitivity of the average size of primary silicon to cooling rate is reduced.How to prevent the oxidation of aluminum during the preparation of Al-P alloy and how to remove large flakes of alumina slag in the melt after modification treatment are the core technologies to be further developed in the future.