CAJ | 학술논문

利用SEM、XRD和TEM研究了激光立体成形(LSF,laser solid forming)Ti_2AlNb基合金的组织演化规律.结果表明:激光立体成形Ti_2AlNb基合金沉积态组织由B2/β_0相(ordered-bcc)和O相(orthorhombic)组成.沉积态的相组成及微观结构从成形试样顶部→中部→底部呈现从B2/β_0固溶体→B2/β_0+O魏氏体 →B2/β_0固溶体的变化,进而使得激光沉积态Ti_2AlNb基合金中间部位的显微硬度值最大,顶部与底部相当.合金显微硬度随激光功率的增大而增大.
이용SEM、XRD화TEM연구료격광입체성형(LSF,laser solid forming)Ti_2AlNb기합금적조직연화규률.결과표명:격광입체성형Ti_2AlNb기합금침적태조직유B2/β_0상(ordered-bcc)화O상(orthorhombic)조성.침적태적상조성급미관결구종성형시양정부→중부→저부정현종B2/β_0고용체→B2/β_0+O위씨체 →B2/β_0고용체적변화,진이사득격광침적태Ti_2AlNb기합금중간부위적현미경도치최대,정부여저부상당.합금현미경도수격광공솔적증대이증대.
Microstructure evolution and hardness distribution of as-deposited Ti2AlNb-based alloy by laser solid forming (LSF) was investigated through SEM,XRD and TEM. The results indicate that the LSFed Ti_2AlNb-based alloy was constituted off B_2/β_0 phase (ordered-bbc) and O phase (orthorhombic). The as-deposited phase in the bottom and top area of the LSF Ti_2AlNb-based alloy sample is B2 phase (Nb-based solid solution),while the phase in the middle area is O phase Widmanstattem. The phase evolution through bottom→ middle→top is B2/β_0→B2/β_0+O→B2/β_0. Therefore,the microhardness of the middle area for LSFed as-deposited Ti_2AlNb-based alloy is maximum,and that of the top and bottom is similar. The microhardness of the alloys increases with the laser power increasing.