镧对A356铝合金变质及其机制的研究

Study on Modification and Mechanism of Lanthanum in A356 Aluminum Alloy

稀土元素具有很多独特的物理和化学性质,在铸造铝合金中添加少量的稀土元素可以起到明显的改性作用。本文利用金相显微镜和XRD研究了金属镧在不同含量,保温时间以及浇铸温度条件下对A356铝合金变质作用的影响。研究结果表明,稀土含量为1.0%变质效果最佳;La具有较长的变质失效时间;浇铸温度对其变质效果影响不大。文中还对稀土元素的变质机制进行了分析和讨论。

Rare earth elements have many particular physical and chemical properties.There is obvious reaction by adding small amount of rare earth elements to as-cast aluminum alloy.In this paper,the modification effect of metal La on A356 aluminum alloy was studied in the condition of different mass fraction of La,different holding time and different pouring temperature by using metallurgical microscope and XRD.The research resumt shows that the modification effect is optimal when 1.0% La is added,and La has long invalidation time of modification.And pouring temperature has little effect on modification.Meanwhile,the mechanism of effect of rare earth element on the modification was analyzed.