论文部分内容阅读
在1 480~1 510℃对Ti-48Al-2Cr-2Nb合金分别进行了0、10、15、20次循环处理,研究了该合金凝固组织的演变规律。结果表明,未处理的合金组织由粗大的片层团组成;随着循环处理次数的增加,Ti-48Al-2Cr-2Nb合金由粗大的片层团向细小的等轴晶转变,且分布更加均匀。分析表明,在循环处理的快速加热阶段,初生晶粒发生了重熔,破碎的枝晶与“母体”分离,可在后续的冷却阶段作为形核质点。与此同时,由于电磁搅拌作用,溶质场和温度场分布均匀,抑制了成分过冷的产生,从而起到了细化晶粒的效果。
The Ti-48Al-2Cr-2Nb alloy was treated at 0, 10, 15 and 20 cycles at 1 480 ~ 1 510 ℃ respectively. The evolution of solidification microstructure of the alloy was studied. The results show that the untreated alloy consists of coarse lamellae. With the increase of the number of cycles, the Ti-48Al-2Cr-2Nb alloy is transformed from coarse lamellae to fine equiaxed lamella and the distribution is more uniform . The analysis shows that during the rapid heating cycle, the primary grains are remelted, and the broken dendrites are separated from the “matrix” and can be used as nucleation sites in the subsequent cooling stage. At the same time, due to electromagnetic stirring, the solute field and the temperature field are evenly distributed, and the overcooling of the component is suppressed, thus the effect of grain refinement is achieved.