Abstract

In this paper, 2Cr13 stainless steels with different Mo contents (x = 0 wt%, 0.5 wt%, 1.0 wt%, 1.5 wt%, 2.0 wt%) were fabricated by Direct Laser Deposition (DLD) technology. The effects of Mo element on the microstructure evolution and comprehensive properties such as corrosion resistance and wear resistance of 2Cr13 stainless steel were investigated in detail. The results showed that the microstructure for the DLD 2Cr13 stainless steel was mainly composed of martensite, ferrite, and a small amount of Mo₂C and Cr₂₃C₆ carbides. With the content of Mo increased from 0.5 to 1.5 wt%, the martensitic microstructure was refined and more dispersed Mo₂C and Cr₂₃C₆ carbides were formed. The average microhardness and corrosion resistance of the DLD 2Cr13-xMo were increased with the Mo content increased from 0 to 1.0 wt%, and then decreased when the Mo content exceeded 1.0 wt%. For the DLD 2Cr13-1.0 wt% Mo, the average microhardness reached up to 620 HV_0.2, and the highest corrosion resistance (self-corrosion potential − 0.34 V) was obtained, in which the self-corrosion potential was 0.05 higher than that of DLD 2Cr13 stainless steel. The wear resistance of the DLD 2Cr13-xMo gradually increased with the increase of the Mo, the wear mass loss of DLD 2Cr13-xMo (x = 1.0 wt%) was only 37% that of DLD 2Cr13 stainless steel.

Graphic Abstract

Schematic diagram of DLD process and the microstructure, properties of 2Cr13 stainless steel with different Mo contents fabricated by DLD technology: (a)The DLD process diagram, (b)The changes of samples microstructure with different Mo contents. The fabrication process of 2Cr13 stainless steel with different Mo content by Direct Laser Deposition and the microstructure evolution process of samples with different Mo content are visually described in this graph. Fig. 1a illustrates in detail the DLD process design for sample preparation using FL-Dlight02-3000W semiconductor laser (maximum power 3000 W, spot size 4mm×4 mm). Fig. 1b shows that the microstructure in the DLD 2Cr13 stainless steel was mainly composed of martensite, ferrite, and a small amount carbides. Combined with the principle of DLD and the effect of Mo addition on microstructure, it is concluded that when Mo content is 1.0wt%, the martensite grain size is smaller, the lath is parallel and the growth direction is consistent, the content of ferrite and carbide is not much, which leads to the highest microhardness and the best corrosion resistance and wear resistance.

中文翻译：

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激光直接沉积法制备2Cr13-xMo不锈钢的组织与性能

摘要

在本文中， 通过直接激光沉积（DLD）技术制备了具有不同 Mo 含量（x = 0 wt%、0.5 wt%、1.0 wt%、1.5 wt%、2.0 wt%）的2Cr13 不锈钢。详细研究了Mo元素对2Cr13不锈钢组织演变和综合性能如2Cr13耐蚀、耐磨性的影响。结果表明，DLD 2Cr13不锈钢的显微组织主要由马氏体、铁素体和少量Mo ₂ C和Cr ₂₃ C ₆碳化物组成。随着 Mo 含量从 0.5 wt% 增加到 1.5 wt%，马氏体组织细化，Mo ₂ C 和 Cr ₂₃ C ₆更加分散形成碳化物。DLD 2Cr13- x Mo的平均显微硬度和耐蚀性随着 Mo 含量从 0 增加到 1.0 wt% 增加，然后当 Mo 含量超过 1.0 wt% 时下降。对于 DLD 2Cr13-1.0 wt% Mo，平均显微硬度达到 620 HV _0.2，获得了最高的耐腐蚀性（自腐蚀电位 - 0.34 V），其中自腐蚀电位高于 0.05 DLD 2Cr13 不锈钢。DLD 2Cr13- x Mo的耐磨性随着Mo含量的增加而逐渐增加，DLD 2Cr13- x Mo ( x  = 1.0 wt%)的磨损质量损失仅为DLD 2Cr13不锈钢的37%。

图形摘要

DLD工艺示意图及DLD工艺制备的不同Mo含量2Cr13不锈钢的显微组织、性能：(a)DLD工艺示意图，(b)不同Mo含量试样微观结构的变化。该图直观地描述了激光直接沉积不同 Mo 含量的 2Cr13 不锈钢的制备过程和不同 Mo 含量样品的组织演变过程。图1a详细说明了使用FL-Dlight02-3000W半导体激光器（最大功率3000W，光斑尺寸4mm×4mm）制备样品的DLD工艺设计。图 1b 显示 DLD 2Cr13 不锈钢的显微组织主要由马氏体、铁素体和少量碳化物组成。结合DLD原理和Mo添加对微观结构的影响，