3D printing of high-strength aluminium alloys
3D printing of high-strength aluminium alloys
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DOI：
10.1038/nature23894
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发表时间：
2017-09-21
期刊：
影响因子：
64.8
通讯作者：
Pollock, Tresa M.
中科院分区：
文献类型：
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作者：
Martin, John H.;Yahata, Brennan D.;Pollock, Tresa M.
基于金属的增材制造或三维（3D）打印是一种跨多个行业的潜在颠覆性技术，包括航空航天，生物医学和汽车行业。逐层构建金属部件增加了设计自由度和制造灵活性，从而实现了复杂的几何形状，增加了产品定制，缩短了上市时间，同时消除了传统的规模经济限制。然而，目前只有少数合金，最相关的是AlSi 10 Mg，TiAl 6V 4，CoCr和Inconel 718，可以可靠地打印（1，2）;今天使用的5，500多种合金中的绝大多数不能进行增材制造，因为打印过程中的熔化和凝固动力学导致无法忍受的微观结构，具有大的柱状晶粒和周期性裂纹（3-5）。在这里，我们证明了这些问题可以通过引入在增材制造过程中控制固化的成核剂的纳米颗粒来解决。我们根据晶体学信息选择了形核剂，并将它们组装到7075和6061系列铝合金粉末上。在用成核剂进行功能化之后，我们发现这些以前与增材制造不兼容的高强度铝合金可以使用选择性激光熔化成功加工。实现了无裂纹、等轴（即，晶粒的长度、宽度和高度大致相等）、细晶粒的微观结构，从而使材料强度与锻造材料相当。我们的金属基增材制造方法适用于各种合金，并且可以使用一系列增材机器来实现。因此，它为广泛的工业适用性提供了基础，包括使用电子束熔化或定向能量沉积技术代替选择性激光熔化的情况，并将使其他合金系统的增材制造成为可能，例如不可焊接的镍超合金和金属间化合物。此外，该技术可用于传统加工，如连接，铸造和注塑，其中凝固裂纹和热裂也是常见问题。
Metal-based additive manufacturing, or three-dimensional (3D) printing, is a potentially disruptive technology across multiple industries, including the aerospace, biomedical and automotive industries. Building up metal components layer by layer increases design freedom and manufacturing flexibility, thereby enabling complex geometries, increased product customization and shorter time to market, while eliminating traditional economy-of-scale constraints. However, currently only a few alloys, the most relevant being AlSi10Mg, TiAl6V4, CoCr and Inconel 718, can be reliably printed(1,2); the vast majority of the more than 5,500 alloys in use today cannot be additively manufactured because the melting and solidification dynamics during the printing process lead to intolerable microstructures with large columnar grains and periodic cracks(3-5). Here we demonstrate that these issues can be resolved by introducing nanoparticles of nucleants that control solidification during additive manufacturing. We selected the nucleants on the basis of crystallographic information and assembled them onto 7075 and 6061 series aluminium alloy powders. After functionalization with the nucleants, we found that these high-strength aluminium alloys, which were previously incompatible with additive manufacturing, could be processed successfully using selective laser melting. Crack-free, equiaxed (that is, with grains roughly equal in length, width and height), fine-grained microstructures were achieved, resulting in material strengths comparable to that of wrought material. Our approach to metal-based additive manufacturing is applicable to a wide range of alloys and can be implemented using a range of additive machines. It thus provides a foundation for broad industrial applicability, including where electron-beam melting or directed-energy-deposition techniques are used instead of selective laser melting, and will enable additive manufacturing of other alloy systems, such as non-weldable nickel superalloys and intermetallics. Furthermore, this technology could be used in conventional processing such as in joining, casting and injection moulding, in which solidification cracking and hot tearing are also common issues.