Abstract NiCrSiB + xY2O3 (x = 0, 0.5, 1, 2, and 5 wt%) alloy samples were fabricated on mild steel via laser additive manufacturing (LAM). The microstructural evolution and mechanical properties of the NiCrSiB + 0.5 wt% Y2O3 alloy were studied systematically in the as-deposited condition and after three different types of post-heat treatment conditions. The scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction results showed that the structures of the as-deposited samples mainly comprised a dendritic matrix of γ-Ni, a continuous interdendritic eutectic of γ + Ni3B, discrete Cr-rich carbides (Cr23C6 and Cr7C3) and a brittle phase (Ni3Si2). With the addition of Y2O3, the volume fraction of the interdendritic eutectic was approximately 19.2, 32.9, 34.5, 34.1 and 26.9%. Y2O3 played an important role in increasing the volume fraction of the eutectic phase and refining the grain size. After the NiCrSiB+0.5 wt% Y2O3 alloy samples were subjected to solution (HT1), solution + aging (HT2) and annealing (HT3) heat treatments, the microstructures evolved considerably. After HT1 and HT2, a carbide (Cr7C3) and brittle phase (Ni3Si2) precipitated on the boundaries of the eutectic structure and between the blocky phases, respectively. After HT3, the grains were refined, and dot-shaped or rod-shaped hard phases (Cr7C3) were uniformly dispersed along the grain boundaries. The microhardness (up to 514.1 HV), wear resistance and microwear properties of the NiCrSiB alloy specimens subjected to HT3 were further improved under the positive action of an appropriate amount of Y2O3. After the heat treatments, the wear mechanism of these samples was mainly adhesive wear.

中文翻译：

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热处理对激光增材制造NiCrSiB/Y2O3合金显微组织演变和摩擦学行为的影响

摘要 NiCrSiB + xY2O3 (x = 0、0.5、1、2 和 5 wt%) 合金样品通过激光增材制造 (LAM) 在低碳钢上制造。NiCrSiB + 0.5 wt% Y2O3 合金的显微组织演变和机械性能在沉积态和三种不同类型的后热处理条件下进行了系统研究。扫描电子显微镜、能量色散X射线光谱和X射线衍射结果表明，沉积态样品的结构主要包括γ-Ni的枝晶基体、γ+Ni3B的连续枝晶间共晶、离散的Cr-富碳化物（Cr23C6 和 Cr7C3）和脆性相（Ni3Si2）。添加 Y2O3 后，枝晶间共晶的体积分数约为 19.2、32.9、34.5、34.1 和 26.9%。Y2O3 在增加共晶相的体积分数和细化晶粒尺寸方面发挥了重要作用。NiCrSiB+0.5 wt% Y2O3 合金样品经过固溶 (HT1)、固溶 + 时效 (HT2) 和退火 (HT3) 热处理后，显微组织发生了显着变化。在HT1和HT2之后，碳化物（Cr7C3）和脆性相（Ni3Si2）分别在共晶组织的边界和块状相之间析出。HT3后晶粒细化，点状或棒状硬质相（Cr7C3）沿晶界均匀分散。在适量Y2O3的积极作用下，经过HT3处理的NiCrSiB合金试样的显微硬度（高达514.1 HV）、耐磨性和显微磨损性能进一步提高。热处理后，