Abstract A dual-gradient bainite steel matrix composite was fabricated by direct laser deposition (DLD) method. The decomposition of WC (reinforcements) during DLD is utilized to adjust the gradient microstructure of the composite. Both the matrix morphology and the reinforcement distribution present obvious gradient variation along the deposition direction. The microhardness and impact toughness exhibit the opposite tendency from the bottom to top of the composite, which shows a good agreement with the gradient microstructure. The surface microhardness and impact toughness of the dual-gradient composite are 510 HV and 75 J/cm2, respectively. The hardness and toughness combination of the composite is superior to most steels for railway frog. The dual-gradient composite has great potential in improving the performance of railway frog.

中文翻译：

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直接激光沉积制备双梯度贝氏体钢基复合材料

摘要 采用激光直接沉积（DLD）法制备了双梯度贝氏体钢基复合材料。DLD 过程中 WC（增强材料）的分解被用来调整复合材料的梯度微观结构。基体形貌和增强体分布均沿沉积方向呈现明显的梯度变化。从复合材料的底部到顶部，显微硬度和冲击韧性表现出相反的趋势，这与梯度微观结构有很好的一致性。双梯度复合材料的表面显微硬度和冲击韧性分别为 510 HV 和 75 J/cm2。该复合材料的硬度和韧性组合优于大多数铁路叉车用钢。双梯度复合材料在提高铁路青蛙的性能方面具有很大的潜力。