Strong yet ductile nanolamellar high-entropy alloys by additive manufacturing
Strong yet ductile nanolamellar high-entropy alloys by additive manufacturing
复制标题
通过增材制造获得坚固且具有延展性的纳米层状高熵合金
DOI：
10.1038/s41586-022-04914-8
复制
发表时间：
2022-08-03
期刊：
影响因子：
64.8
通讯作者：
Chen, Wen
中科院分区：
文献类型：
--
作者：
Ren, Jie;Zhang, Yin;Chen, Wen
增材制造为工程应用一层一层地生产网状部件（1-7）。激光粉末床熔合（L-PBF）金属合金的增材制造涉及到大的温度梯度和快速冷却（2,6），这使得微观结构的细化在纳米尺度上达到高强度。然而，由激光增材制造生产的高强度纳米结构合金通常具有有限的延展性(3)。在这里，我们使用L-PBF打印了AlCoCrFeNi2.1的双相纳米层状高熵合金（HEAs），该合金具有约1.3千兆帕的高屈服强度和约14%的大均匀伸长率，超过了其他最先进的增材制造金属合金。高屈服强度源于面心立方和体心立方纳米片交替构成的双相结构的强强化效应；体心立方纳米片比面心立方纳米片表现出更高的强度和更高的硬化速率。大的拉伸延展性是由于打印的双相纳米片嵌入微尺度共晶集落的分层微观结构具有高的加工硬化能力，这些结构具有几乎随机的取向，以促进各向同性的力学性能。对增材制造HEAs变形行为的机理研究对开发具有优异力学性能的分层、双相和多相纳米结构合金具有广泛的意义。
Additive manufacturing produces net-shaped components layer by layer for engineering applications(1-7). The additive manufacture of metal alloys by laser powder bed fusion (L-PBF) involves large temperature gradients and rapid cooling(2,6), which enables microstructural refinement at the nanoscale to achieve high strength. However, high-strength nanostructured alloys produced by laser additive manufacturing often have limited ductility(3). Here we use L-PBF to print dual-phase nanolamellar high-entropy alloys (HEAs) of AlCoCrFeNi2.1 that exhibit a combination of a high yield strength of about 1.3 gigapascals and a large uniform elongation of about 14 per cent, which surpasses those of other state-of-the-art additively manufactured metal alloys. The high yield strength stems from the strong strengthening effects of the dual-phase structures that consist of alternating face-centred cubic and body-centred cubic nanolamellae; the body-centred cubic nanolamellae exhibit higher strengths and higher hardening rates than the face-centred cubic nanolamellae. The large tensile ductility arises owing to the high work-hardening capability of the as-printed hierarchical microstructures in the form of dual-phase nanolamellae embedded in microscale eutectic colonies, which have nearly random orientations to promote isotropic mechanical properties. The mechanistic insights into the deformation behaviour of additively manufactured HEAs have broad implications for the development of hierarchical, dual- and multi-phase, nanostructured alloys with exceptional mechanical properties.