Gradient-structured (GS) materials are attracting much interest due to their ability to deliver stronger and more ductile steels. However, the fabrication of GS H13 steels via direct laser deposition (DLD) has been rarely studied although they are widely employed as hot-work steels for use at high temperatures. Therefore, in this investigation, three scanning strategies with different thermal cycling protocols were applied to fabricate GS H13 steels using DLD and the effect of these conditions on the microstructural evolution and mechanical properties of the resulting steels was evaluated. Using an optimised scanning strategy with suitable time intervals between individual layers and incident laser energy, it can be obtained gradient microstructures with grain sizes ranging from ∼7.1 μm at the top to ∼4.7 μm at the bottom. The sample surfaces constituted of martensite while the interior was transformed from martensite into tempered martensite and nanoprecipitates (Cr₂₃C₆) after thermal cycling. Thus, the sample surfaces exhibited a high ultimate strength (1981 MPa) and hardness (∼660 HV), whereas the interior exhibited better plasticity (∼12%). Finally, the methodology outlined in this article provides a strategy to control thermal cycling to achieve the necessary gradient in the microstructure and mechanical properties of DLD H13 steels.

梯度结构（GS）材料由于能够提供更坚固，更易延展的钢材而备受关注。然而，尽管通过直接激光沉积（DLD）制造GS H13钢已被广泛用作高温工作的热作钢，但很少进行研究。因此，在这项研究中，使用DLD制备了三种具有不同热循环规程的扫描策略来制造GS H13钢，并评估了这些条件对所得钢的微观组织演变和力学性能的影响。使用优化的扫描策略，在各个层之间具有适当的时间间隔并入射激光能量，可以获得梯度晶粒结构，其晶粒尺寸从顶部的〜7.1μm到底部的〜4.7μm。₂₃ C ₆）后进行热循环。因此，样品表面表现出高的极限强度（1981 MPa）和硬度（〜660 HV），而内部表现出更好的可塑性（〜12％）。最后，本文概述的方法提供了一种控制热循环的策略，以在DLD H13钢的组织和力学性能中实现必要的梯度。