Grain structure evolution in Inconel 718 during selective electron beam melting
Grain structure evolution in Inconel 718 during selective electron beam melting
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DOI：
10.1016/j.msea.2016.05.046
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发表时间：
2016-06-21
期刊：
影响因子：
6.4
通讯作者：
Koerner, C.
中科院分区：
文献类型：
--
作者：
Helmer, H.;Bauereiss, A.;Koerner, C.
选择性电子束熔化（SEBM）是一种增材制造方法，将金属粉末制成通常为50克的层状复杂零件。电子束用于加热（约900摄氏度的建筑温度）和材料的选择性熔化。熔池中复杂的热、水动力条件是晶粒结构演变的结果。我们展示了如何使用不同的扫描策略来产生在构建方向上具有高纹理的柱状晶粒结构或等轴细晶粒结构。采用数值模拟的方法研究了形成不同晶粒结构的基本机理。结果表明，通过扫描策略可以改变凝固过程中热梯度的方向，从而获得外延生长或杂散晶粒。我们表明，局部改变零件的晶粒结构是可能的，从而允许定制机械性能。(C) 2016 Elsevier B.V.版权所有
Selective electron beam melting (SEBM) is an additive manufacturing method where complex parts are built from metal powders in layers of typically 50 gm. An electron beam is used for heating (about 900 degrees C building temperature) and selective melting of the material. The grain structure evolution is a result of the complex thermal and hydrodynamic conditions in the melt pool. We show how different scanning strategies can be used to produce either a columnar grain structure with a high texture in building direction or an equiaxed fine grained structure. Numerical simulations of the selective melting process are applied to study the fundamental mechanisms responsible for differing grain structures. It is shown, that the direction of the thermal gradient during solidification can be altered by scanning strategies to acquire either epitaxial growth or stray grains. We show that it is possible to locally alter the grain structure of a part, thus allowing tailoring of the mechanical properties. (C) 2016 Elsevier B.V. All rights reserved.