共晶组织强化NbMoZrVSi_(x)难熔高熵合金的摩擦磨损性能及磨损机理  

Tribological Property and Wear Mechanism of NbMoZrVSix Refractory High-Entropy Alloy Strengthened by Eutectic Structure

作　　者：王瀚铭 杜银 裴旭辉 王海丰[1] WANG Hanming;DU Yin;PEI Xuhui;WANG Haifeng(Center of Advanced Lubrication and Seal Materials,State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xi'an 710072,China)

机构地区：[1]西北工业大学凝固技术国家重点实验室先进润滑与密封材料研究中心,西安710072

出　　处：《金属学报》2024年第7期937-946,共10页Acta Metallurgica Sinica

基　　金：国家自然科学基金项目No.51975474;中央高校基本科研业务费项目No.3102019JC001。

摘　　要：难熔高熵合金共晶强化组织的形成机制及其对室温摩擦磨损行为的研究,可为后续开发具有优异摩擦磨损性能的难熔高熵合金提供新的设计思路。本工作利用摩擦试验机、SEM和XPS等手段研究了微量Si元素添加对NbMoZrV难熔高熵合金室温摩擦学性能的影响规律,分析了不同硅化物的析出形态对合金磨损机理的影响。结果表明:适量Si元素添加时,NbMoZrVSi_(0.1)难熔高熵合金的bcc基体晶界处会均匀析出由Zr-Zr3Si相组成的共晶组织结构,该共晶组织会显著提高合金的硬度和耐磨性。不同于NbMoZrV、NbMoZrVSi_(0.05)和NbMoZrVSi_(0.2)合金波动较大的摩擦学行为,在不同加载力下,含有共晶组织结构的NbMoZrVSi_(0.1)难熔高熵合金在室温滑动干摩擦实验中表现出了稳定的摩擦系数和磨损率。磨损机理分析表明,Zr-Zr3Si共晶组织的形成会抑制NbMoZrVSi_(0.1)难熔高熵合金在摩擦过程中的裂纹萌生扩展以及脆性剥落,并促进随后均匀氧化的发生,使得其仅表现出轻微磨粒磨损的特征,从而使其耐磨性得到显著提升。In recent years,refractory high-entropy alloys(RHEAs)have gained widespread attention owing to their high structural stability and excellent mechanical properties at both room and elevated temperatures.However,their wear resistance at room temperature is often poor due to their fragility.In this study,the effect of adding small amounts of silicon(Si)to NbMoZrV RHEA on its tribological properties and wear mechanism at room temperature have been studied using various techniques including tribometer,SEM,and XPS.The results showed that adding a moderate amount of Si induced the homogeneous precipitation of a eutectic structure composed of Zr-Zr3Si phase at the bcc matrix grain boundary.This eutectic structure significantly improved the hardness and wear resistance of the NbMoZrVSi0.1 RHEA.Unlike the poor tribological behavior observed in NbMoZrVSi0.05 and NbMoZrVSi0.2 RHEAs,the NbMoZrVSi0.1 RHEA exhibited stable coefficient of friction and wear rate under dry sliding wear test at room temperature with varying normal loads.The Zr-Zr3Si eutectic structure effectively inhibited the initiation and propagation of cracks and brittle spalling during the sliding wear test,resulting in only slight abrasive wear of the NbMoZrVSi0.1 RHEA.Moreover,the mechanism promoted the subsequent homogeneous oxidation of the worn surface.

关 键 词：难熔高熵合金 共晶组织 耐磨性 磨粒磨损 

分 类 号：TG113[金属学及工艺—物理冶金]