Microstructure and Crystallographic Texture of Laser Additive Manufactured Nickel-Based Superalloys with Different Scanning Strategies
Microstructure and Crystallographic Texture of Laser Additive Manufactured Nickel-Based Superalloys with Different Scanning Strategies
复制标题
不同扫描策略激光增材制造镍基高温合金的微观结构和晶体织构
DOI：
10.3390/cryst11060591
复制
发表时间：
2021-06-01
期刊：
影响因子：
2.7
通讯作者：
Song, Lijun
中科院分区：
文献类型：
--
作者：
Liu, Xingbo;Xiao, Hui;Song, Lijun
金属添加剂生产过程中凝固组织和晶体织构的控制是一项具有挑战性的工作，引起了越来越多的研究人员的兴趣。采用单向和横向两种扫描方式对Inconel718合金准连续波激光添加制造(QCW-LAM)过程中的凝固组织和晶体织构进行了控制。结果表明，扫描策略对凝固组织和织构有很强的依赖性。SDS具有典型的纤维织构，具有单向柱状晶，而CDS具有更多的无序织构，具有单向和多向的混合织构。此外，SDS促进了柱状枝晶的连续外延生长，形成了线状分布的Laves相颗粒，而CDS则导致了交替分布的链状和离散的Laves相颗粒。不同扫描策略引起的熔池边界堆积特征的变化和热流方向的切换对枝晶的外延生长和制件的最终凝固组织起着至关重要的作用。
Control of solidification structure and crystallographic texture during metal additive manufacturing is a challenging work which attracts the increasing interest of researchers. In the present work, two kinds of scanning strategies (i.e., single-directional scanning (SDS) and cross-directional scanning (CDS) were used to control the solidification structure and crystallographic texture during quasi-continuous-wave laser additive manufacturing (QCW-LAM) of Inconel 718. The results show that the solidification structure and texture are strongly dependent on scanning strategies. The SDS develops a typical fiber texture with unidirectional columnar grains, whereas the CDS develops a more random texture with a mixture of unidirectional and multidirectional grains. In addition, the SDS promotes the continuously epitaxial growth of columnar dendrites and results in the linearly distributed Laves phase particles, while the CDS leads to the alternately distributed Laves phase particles with chain-like morphology and discrete morphology. The changed stacking features of molten-pool boundary and the switched heat flow direction caused by different scanning strategies plays a crucial role on the epitaxial growth of dendrites and the final solidification structure of the fabricated parts.