Al-3B中间合金是亚共晶Al-Si合金的高效细化剂之一.实验研究了Al-3B中间合金中未溶AlB2颗粒对Al-7Si合金晶粒细化的影响.结果表明,AlB2颗粒的数目和沉降对晶粒细化效果都有重要影响.在实验结果和理论分析基础上,提出了Al-3B中间合金对亚共晶Al-Si合金晶粒细化的新机制,认为通过共晶反应形成的“Al-AlB2”包覆结构是导致晶粒细化的直接原因,未溶的AlB2颗粒是α(Al)相的间接行核基底.%Al-3B master alloy is a kind of efficient grain refiner for hypoeutectic Al-Si alloys.Experiments were carried out to evaluate the effect of undissolved AlB2 particles in Al-3B master alloy on the grain refinement ofAl-7Si.It is found that the number and the settlement of AlB2 particles in the melt all have effect on the grain refining efficiency.On the basis of experiments and theoretical analysis,a new grain refinement mechanism was proposed to explain the grain refinement action of Al-3B on hypoeutectic Al-Si alloys.The formation of ‘Al-AlB2' shell structure is the direct reason for grain refinement and the undissolved AlB2 particles is the indirect nucleating base for subsequent α(Al) phase.
展开▼
