A lightweight Fe–Mn–Al–C austenitic steel with ultra-high strength and ductility fabricated via laser powder bed fusion
A lightweight Fe–Mn–Al–C austenitic steel with ultra-high strength and ductility fabricated via laser powder bed fusion
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DOI：
10.1016/j.msea.2023.145007
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发表时间：
2023-04
期刊：
影响因子：
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通讯作者：
R. Seede;Austin Whitt;J. Ye;S. Gibbons;P. Flater;B. Gaskey;A. Elwany;R. Arróyave;I. Karaman
中科院分区：
文献类型：
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作者：
R. Seede;Austin Whitt;J. Ye;S. Gibbons;P. Flater;B. Gaskey;A. Elwany;R. Arróyave;I. Karaman
轻质Fe-Mn-Al-C钢已成为国防和汽车工业的重要研究课题。这些合金可以保持高强度和延展性，同时还可以减轻结构应用中的重量。常规处理的具有高Al含量（约9wt%）的Fe-Mn-Al-C奥氏体钢表现出大于1.5GPa的强度和35%的伸长率。最近的几项研究已经证明了使用激光粉末床熔融（L-PBF）增材制造（AM）制造钢部件的成功，该增材制造可以生成具有复杂几何形状的近净形部件，并且能够进行局部微观结构控制。然而，对Fe-Mn-Al-C合金的L-PBF处理的研究集中在代表经历相变诱导塑性（TRIP）和孪生诱导塑性（TCEP）的合金的低Al含量（<5wt%）组成区域。本文研究了L-PBF工艺对Fe-30 Mn-9Al-1 Si-0.5Mo-0.9C奥氏体钢显微组织和力学性能的影响。采用工艺优化框架来确定将导致>99%密度部件的理想L-PBF处理空间。实施这一框架导致在广泛的工艺参数范围内制造的接近完全致密的试样。此外，采用两种双向扫描旋转策略（90°和67°）来了解它们对该材料中的织构和各向异性的影响。打印的标本表现出相当大的加工硬化特性，平均强度高达1.3 GPa和36%的伸长率在建设方向。然而，在构建方向上取向的凝固微裂纹导致拉伸强度和延展性的各向异性，导致垂直于构建方向的平均强度为1.1 GPa和伸长率为20%。本文提出的Fe-30 Mn-9Al-1 Si-0.5Mo-0.9C的成功L-PBF制造有望为结构应用中的重量减轻开辟新的途径，并对部件拓扑结构进行高度控制。
Lightweight Fe–Mn–Al–C steels have become a topic of significant interest for the defense and automotive industries. These alloys can maintain high strength and ductility while also reducing weight in structural applications. Conventionally processed Fe–Mn–Al–C austenitic steels with high Al content (∼9 wt%) demonstrate greater than 1.5 GPa strength with 35% elongation. Several recent studies have demonstrated success in fabricating steel parts using laser powder bed fusion (L-PBF) additive manufacturing (AM), which can generate near-net-shape components with complex geometries and is capable of local microstructural control. However, studies on L-PBF processing of Fe–Mn–Al–C alloys have focused on low Al content (<5 wt%) compositional regimes representing alloys that undergo transformation-induced plasticity (TRIP) and twinning-induced plasticity (TWIP). Here, we present the effects of L-PBF processing on the microstructure and mechanical properties of an Fe–30Mn–9Al–1Si-0.5Mo-0.9C austenitic steel. A process optimization framework is employed to determine an ideal L-PBF processing space that will result in >99% density parts. Implementing this framework resulted in near-fully dense specimens fabricated over a broad range of process parameters. Additionally, two bi-directional scan rotation strategies (90° and 67°) were applied to understand their effects on texture and anisotropy in this material. As-printed specimens displayed considerable work-hardening characteristics with average strengths of up to 1.3 GPa and 36% elongation in the build direction. However, solidification microcracks oriented in the build direction resulted in anisotropy in tensile strength and ductility resulting in average strengths of 1.1 GPa and 20% elongation perpendicular to the build direction. The successful L-PBF fabrication of Fe–30Mn–9Al–1Si-0.5Mo-0.9C presented here is expected to open new avenues for weight reduction in structural applications with a high degree of control over part topology.