Epitaxial re-solidification of laser-melted Ni-Mn-Ga single crystal
Epitaxial re-solidification of laser-melted Ni-Mn-Ga single crystal
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DOI：
10.1016/j.actamat.2021.117236
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发表时间：
2021-08
期刊：
影响因子：
9.4
通讯作者：
J. Toman;D. Pagan;P. Müllner;M. Chmielus
中科院分区：
文献类型：
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作者：
J. Toman;D. Pagan;P. Müllner;M. Chmielus
磁性形状记忆合金（MSMA）的增材制造（AM）允许在MSMA部件的设计中更充分地使用几何形状，并避免与单晶生产相关的偏析和高成本。虽然在MSMA的AM中的大多数研究努力追求功能性泡沫或多晶，但在液相AM期间的外延生长可以实现完全致密的单晶MSMA部件，并具有完全阻断应力的相关可用性。在激光功率和速度的几种工艺参数组合下，采用移动激光光斑熔化Ni 51 Mn 24.4Ga 24.6单晶。虽然用较低激光行进速度产生的轨迹几乎完全是外延的，但用最高速度（10 mm/s）产生的轨迹包括非外延柱状晶粒和轨迹顶部的晶粒。基于同步加速器的高能衍射显微镜（HEDM）的实验表明，镶嵌扩展的外延材料是略高于周围的非再固化材料。我们的结果表明，使用全熔化激光加工可以以最小的晶粒含量外延生长Ni-Mn-Ga。
Additive manufacturing (AM) of magnetic shape-memory alloys (MSMAs) allows fuller use of geometry in the design of MSMA parts and avoids the segregation and high cost associated with single crystal production. While most research effort in AM of MSMAs pursues functional foams or polycrystals, epitaxial growth during liquid-phase AM may enable fully-dense single-crystalline MSMA parts, with associated availability of the full blocking stress. We melted a Ni51Mn24.4Ga24.6single crystal with a moving laser spot under several process parameter combinations of laser power and velocity. While tracks created with lower laser travel velocity were almost entirely epitaxial, the track created with highest velocity (10 mm/s) included non-epitaxial columnar grains and grains at the top of the track. Synchrotron-based high-energy diffraction microscopy (HEDM) experiments revealed that mosaic spread of epitaxial material was slightly higher than that of surrounding non-re-solidified material. Our results demonstrate epitaxial growth of Ni-Mn-Ga with minimal grain content using full-melting laser processing.