Investigation Of Micro-structure And Mechanical Properties Of Hypoeutectic Al-Si Alloy Prepared With Electrolytic Low-titanium Aluminum Alloy

The grain refining mechanism of Al-Si alloys and the addition method of popular grain refiners containing Ti and/or B are firstly introduced in this paper. The influence of different master alloys containing Ti and/or B and the Ti/B mass ratio on the grain refining effect in Al-Si alloys are also commented. In addition, the author yet describes a new method of Ti addition by means of electrolytic low-titanium aluminum alloy (ELTAA). Compared with the conventional method of Ti addition, the Ti addition by electrolysis has a lot of advantages, such as low cost, little pollution, high Ti absorption and so on. Based on the investigations that have been made, the microstructure and the mechanical properties of the hypoeutectic Al-Si alloy prepared with ELTAA are studied. The followings are the main studying results of this paper.1.The grain refining effects of Ti addition by electrolysis, Al-5Ti and A1-5Ti-1B master alloy in Al-9%Si alloy prepared with pure aluminum are investigated, and compared with that of A1-4B master alloy in Al-9%Si alloy prepared with ELTAA. The results show that the grain refining effect of Ti addition by electrolysis is superior to that of Al-5Ti master alloy. The microstructures of these two kinds of Al-9%Si alloys containing Ti are obviously finer than that of Al-9%Si alloy without Ti addtion. The grain refining ability of Al-5Ti-1B master alloy is significantly better than those of Ti addition by electrolysis and by Al-5Ti master alloy. When B addition is made in terms of the Ti/B mass ratio of 5:1, the grain refining effect of A1-4B master alloy in Al-9%Si alloy prepared with ELTAA is even superior to that of Al-5Ti-1B master alloy.2. The influence of B content on the grain refining effects in Al-9%Si alloys prepared with pure aluminum and with ELTAA are investigated respectively in this paper. For the alloy prepared with pure aluminum, when the addition content of B is 0.06%, a good grain refining effect can be obtained, and is superior to that of only Ti addition; For the alloy prepared with ELTAA, when the addition content of B is 0.03%, the grain refining effect has been better...