The effect of a spot melt strategy on the solidification texture, variant selection, phase fraction, and their variations along the build height was investigated in comparison to a conventional linear melt strategy. Ti-6Al-4V alloy samples were manufactured by an electron-beam powder bed fusion process using two different melt strategies and characterized using high-energy synchrotron x-ray diffraction. The linear and spot melt cases resulted in β<100> cube and fiber textures, respectively, with the cube/fiber axis nearly parallel to the build direction. The α phase exhibited Burgers orientation relationship (BOR) with the parent β phase for both melt strategies. Although all of the key texture components and the BOR between the α and β phases were consistently observed in both cases along the build height, there were several measurable differences between the two. At the top of the build height, the β<100> build texture intensity was stronger in the linear case. However, the texture intensity in the linear case decreased gradually from the top to near the substrate, whereas the spot melt case did not show this trend. Moreover, the BOR was examined along the build height and the results showed that there is a distinct variant selection in the spot melt case, unlike the linear case. Specifically, the planar variants sharing ${(\bar{1}01)}_{\beta }$|| ${(0002)}_{\alpha }$ with ${[\bar{2}\bar{2}\bar{2}]}_{\beta }$ and ${[2\bar{2}2]}_{\beta }$ were the most prominent in the spot melt, but no preference was identified in the directional variants. The β phase fraction was slightly lower in the spot melt case compared to the linear case. In both the cases, the β phase fraction decreased moving towards the substrate but remained significantly higher than that of the powder feedstock. Overall, the novel spot melt strategy produced a more homogeneous microstructure in terms of both the phase fraction and texture across the build height.

与传统的线性熔化策略相比，研究了点熔化策略对凝固织构、变体选择、相分数及其沿构建高度的变化的影响。Ti-6Al-4V 合金样品是通过电子束粉末床熔融工艺使用两种不同的熔体策略制造的，并使用高能同步加速器 X 射线衍射进行表征。线性和点熔情况分别导致 β<100> 立方体和纤维织构，立方体/纤维轴几乎平行于构建方向。对于两种熔体策略，α 相与母体 β 相均表现出 Burgers 取向关系 (BOR)。尽管在两种情况下沿构建高度一致地观察到所有关键纹理成分以及 α 和 β 相之间的 BOR，两者之间存在若干可衡量的差异。在构建高度的顶部，β<100> 构建纹理强度在线性情况下更强。然而，线性情况下的织构强度从顶部到基板附近逐渐降低，而点熔化情况没有显示出这种趋势。此外，沿着构建高度检查了 BOR，结果表明，与线性情况不同，在点熔化情况下存在明显的变体选择。具体来说，平面变体共享 沿着构建高度检查 BOR，结果表明，与线性情况不同，在点熔化情况下存在明显的变体选择。具体来说，平面变体共享 沿着构建高度检查 BOR，结果表明，与线性情况不同，在点熔化情况下存在明显的变体选择。具体来说，平面变体共享${(\bar{1}01)}_{\beta }$|| ${(0002)}_{\alpha }$ 和 ${[\bar{2}\bar{2}\bar{2}]}_{\beta }$ 和 ${[2\bar{2}2]}_{\beta }$是在现场熔化中最突出的，但在定向变体中没有确定偏好。与线性情况相比，点熔化情况下的 β 相分数略低。在这两种情况下，β 相分数向基材移动时减少，但仍显着高于粉末原料。总体而言，新的点熔策略在整个构建高度的相分数和纹理方面产生了更均匀的微观结构。