摘要
A novel A1-Ti-C master alloy containing A14C3 and TiC particle clusters, which exhibits great refining potential for Mg, was prepared. With the addition of 2% A1-Ti-C master alloy, the grains transform to equiaxed crystal with a diameter of （110-a：17） ~tm. The results indicate that A14C3 and TiC particle cluster, rather than a single particle, plays an important role in the refining process. Compared with the simplex smooth nucleating substrate, concave regions on the particle cluster provide easier route for the transformation from liquid Mg atoms to stable nucleus. Nucleus with a small size can also reach the critical nucleation radius when they attach on the concave regions of the substrate. A14C3 and TiC particle clusters thus become more favorable nucleating substrate for a-Mg grains.
制备一种含有Al4C3和Ti C颗粒团的Al-Ti-C中间合金,该合金对纯镁有很好的细化作用。当中间合金加入量为2%时,镁晶粒细化为(110±17)μm的等轴晶。通过分析可知,Al4C3和Ti C组成的颗粒团在细化过程中发挥了重要作用。与单个、光滑的形核颗粒相比,颗粒团上的凹面区域增加了熔体中的液态镁原子向稳定晶核转变的可能性,依附在颗粒团凹面区域尺寸较小的晶胚也可以满足临界形核半径的要求,这使得Al4C3和TiC颗粒团成为镁晶粒更理想的形核基底。
基金
Project(DUT15JJ(G)01) supported by the Fundamental Research Funds for the Central Universities,China
Project(2009AA03Z525) supported by the National High-tech Research and Development Program of China
