In a recent study led by Lawrence Livermore National Laboratory (LLNL), scientists have discovered a way of making stainless steel two to three times stronger than usual. The method takes advantage of the unique grain structure of stainless steel parts when 3D printed using粉床融合（PBF）技术。
Though the goal of the research was not to make production better than traditional manufacturing Alex Hamza, the LLNL scientist who oversaw some of the production on the project, says “it just worked out that way.”
Equipped with this new knowledge, the same principles can be applied to other 3D printable metal alloys, potentially benefiting many high value additive manufacturing adopters in aerospace, automotive, medicine and defense.
反对谷物
The grain of a 3D printed stainless steel part differs greatly to how it appears in a machined part. In theLLNL article on the projectHamza将其描述为“就像彩色玻璃窗。”
Though this property is well known in the industry as the result of welding, a closer look at the grain gleaned crucial information relating to the material’s performance. Hamza explains, “The grains are not very small, but the cellular structures and other defects inside the grains that are commonly seen in welding seem to be controlling the properties.”
“这是发现。”
Clearing up pores
通过检查不锈钢样品的颗粒，研究人员确定了在3D打印过程中创建的毛孔，否则这些孔就不会存在于机加工部分中。LLNL材料科学家兼首席作者莫里斯·王（Morris Wang）解释说：“为了使您要打印的所有组件有用，您需要至少拥有与传统冶金所具有的材料属性相同。”
In order to improve porosity levels, the researchers performed a process of density optimization, manipulating the structure within the grain.
Wang adds, “We were able to 3D print real components in the lab with 316L stainless steel, and the material’s performance was actually better than those made with the traditional approach.”
“这确实是一个很大的跳跃。它使添加剂制造非常吸引人，并填补了主要空白。”
A Marine grade material
LLNL在材料建模，仿真和实验方面的丰富经验使这一发现成为可能，这是一种产生许多其他的专业知识增材制造突破包括对“飞溅效果。”该项目还受益于与佐治亚理工大学，俄勒冈州立大学和埃姆斯国家实验室的合作spherically superior powdered metalmaterials.
LLNL和合作伙伴研究的不锈钢特定等级是316L型 - 一种金属因其在腐蚀性环境和延性中的性能而受到称赞，这比在压力下破裂的其他金属更容易使用。316L抵抗盐水损害的能力使其成为海洋级材料，这是需要严格灭菌的医疗应用的首选。
有关本文讨论的研究的完整论文在线发表自然材料。It is co-authored by Y. Morris Wang, Thomas Voisin, Joseph T. McKeown, Jianchao Ye, Nicholas P. Calta, Zan Li, Zhi Zeng, Yin Zhang, Wen Chen, Tien Tran Roehling, Ryan T. Ott, Melissa K. Santala, Philip J. Depond, Manyalibo J. Matthew, Alex V. Hamza and Ting Zhu.
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Featured image shows a mechanical test of the added strength 3D printed stainless steel. Photo by Kate Hunts/LLNL.
