This work aims at depositing single-layer H13 tool steel cladding on a precipitation hardening copper‑beryllium (CuBe) alloy substrate using direct laser metal deposition (DLMD). The process parameters, i.e. laser power, powder feed rate, overlap ratio, and substrate temperature were optimized at the scan speed of 1000 mm/min for both single-track and single-layer cladding. The clad quality was evaluated according to i) geometrical features ii) cladding defects, iii) interfacial adhesion, and iv) substrate over-aging.

The energy-mass balance was sensitive to the variation of processing parameters especially when the high-reflectivity CuBe substrate was used. The dense and sound cladding was eventually deposited after parameter optimization. Substrate preheating inhibited crack formation. However, the higher the preheating temperature, the larger the substrate softening due to over-aging: using 150 °C, the substrate hardness decreased by 13% down to 2.7 mm in depth, while at 250 °C it decreased by 40% down to the same depth. The single-layer H13 clad layer produced at a 150 °C-preheating temperature showed a better load-bearing capability than CuBe alloy substrate, up to 20 kN indentation load. Meanwhile, its surface hardness and wear resistance were remarkably higher.

这项工作旨在使用直接激光金属沉积 (DLMD)在沉淀硬化铜铍 (CuBe) 合金基底上沉积单层 H13 工具钢熔覆层。工艺参数，即激光功率、送粉率、重叠率和基体温度，在扫描速度为 1000 mm/min 时对单道和单层熔覆进行了优化。根据 i) 几何特征 ii) 包层缺陷、iii) 界面粘附性和 iv) 衬底过度老化来评估包层质量。

能量-质量平衡对工艺参数的变化很敏感，尤其是在使用高反射率 CuBe 基板时。经过参数优化后，最终沉积了致密而完好的包层。基板预热抑制了裂纹的形成。然而，预热温度越高，基材因过时效而软化的程度越大：使用 150 °C，基材硬度下降 13%，深度为 2.7 mm，而在 250 °C 时，硬度下降 40%，降至相同的深度。在 150 °C 预热温度下生产的单层 H13 覆层显示出比 CuBe 合金基板更好的承载能力，高达 20 kN 的压痕载荷。同时，其表面硬度和耐磨性显着提高。