为满足航空航天领域同一部件不同部位的性能适用其使用环境的特殊需求, 梯度结构材料逐渐引起国内外学者的广泛关注。采用激光立体成形技术制备TA15-Ti2AlNb梯度结构材料, 研究了TA15-Ti2AlNb双合金材料的微观组织演化和显微硬度。结果表明：随着Al、Nb含量的增大, 激光立体成形沉积态TA15-Ti2AlNb双合金从TA15合金侧到Ti2AlNb基合金侧相的转变依次为α和β相, α、α2和β/B2相, α2和β/B2相, α2、β/B2和O相及α2和B2+O相。且晶粒形貌从外延生长的柱状晶逐渐转变为各向同性生长的等轴晶, 发生显著的CET转变。沉积过程中热影响引起的元素扩散是导致最终稀释区元素分布的主要影响因素, 最终导致沉积试样的微观组织和相组成发生显著改变。

In order to meet the special needs of the environment for the different parts of the same component in the aerospace industry, gradient structural materials have gradually attracted widespread attention from scholars at home and abroad. In this paper, the TA15-Ti2AlNb gradient structure material was prepared by laser solid forming. The microstructure evolution and microhardness of TA15-Ti2AlNb dual alloy materials were studied. The results show that with the increase of Al and Nb content, the transformation of the laser solid formed TA15-Ti2AlNb dual alloy from the TA15 alloy side to the Ti2AlNb-based alloy side phase is α and β phase, α, α2 and β/B2 phases , α2 and β/B2 phases, α2, β/B2 and O phases, and α2 and B2+O phases. And the grain morphology gradually changes from epitaxially grown columnar crystals to isotropic crystals of isotropic growth, and a significant CET transition occurs. The diffusion of elements caused by thermal effect during the deposited process is the main factor for the distribution of elements in the final dilution zone, which ultimately leads to a significant change in the microstructure and phase composition of the deposited samples.