Laser additive manufacturing is attractive for the production of complex, three-dimensional parts from metallic powder using a computer-aided design model 1 – 3 . The approach enables the digital control of the processing parameters and thus the resulting alloy’s microstructure, for example, by using high cooling rates and cyclic re-heating 4 – 10 . We recently showed that this cyclic re-heating, the so-called intrinsic heat treatment, can trigger nickel-aluminium precipitation in an iron–nickel–aluminium alloy in situ during laser additive manufacturing 9 . Here we report a Fe19Ni5Ti (weight per cent) steel tailor-designed for laser additive manufacturing. This steel is hardened in situ by nickel-titanium nanoprecipitation, and martensite is also formed in situ, starting at a readily accessible temperature of 200 degrees Celsius. Local control of both the nanoprecipitation and the martensitic transformation during the fabrication leads to complex microstructure hierarchies across multiple length scales, from approximately 100-micrometre-thick layers down to nanoscale precipitates. Inspired by ancient Damascus steels 11 – 14 —which have hard and soft layers, originally introduced via the folding and forging techniques of skilled blacksmiths—we produced a material consisting of alternating soft and hard layers. Our material has a tensile strength of 1,300 megapascals and 10 per cent elongation, showing superior mechanical properties to those of ancient Damascus steel 12 . The principles of in situ precipitation strengthening and local microstructure control used here can be applied to a wide range of precipitation-hardened alloys and different additive manufacturing processes. A Damascus-like steel consisting of alternating hard and soft layers is created by using a laser additive manufacturing technique and digital control of the processing parameters.

中文翻译：

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通过增材制造的高强度大马士革钢

激光增材制造对于使用计算机辅助设计模型 1 – 3 从金属粉末生产复杂的三维零件具有吸引力。该方法可以对加工参数进行数字控制，从而对所得合金的微观结构进行数字控制，例如，通过使用高冷却速率和循环再加热 4 – 10。我们最近表明，这种循环再加热，即所谓的本征热处理，可以在激光增材制造过程中在铁镍铝合金中原位触发镍铝沉淀 9 。在这里，我们报告了一种为激光增材制造量身定制的 Fe19Ni5Ti（重量百分比）钢。这种钢通过镍钛纳米沉淀进行原位硬化，马氏体也在原位形成，起始温度为 200 摄氏度。在制造过程中对纳米沉淀和马氏体转变的局部控制导致跨多个长度尺度的复杂微观结构层次，从大约 100 微米厚的层到纳米级沉淀。受古代大马士革钢 11 - 14 的启发——它们有硬层和软层，最初是通过熟练铁匠的折叠和锻造技术引入的——我们生产了一种由交替的软层和硬层组成的材料。我们的材料具有 1,300 兆帕的抗拉强度和 10% 的伸长率，显示出优于古代大马士革钢 12 的机械性能。此处使用的原位沉淀强化和局部微观结构控制原理可应用于各种沉淀硬化合金和不同的增材制造工艺。通过使用激光增材制造技术和加工参数的数字控制，制造出一种由交替的硬层和软层组成的大马士革钢。