TA1钛合金的表面复合强化与磨损行为研究  

Surface Composite Strengthening and Wear Behavior of TA1 Titanium Alloy

作　　者：刘港 刘静[1] 代燕 杨峰[1] 陈丽 LIU Gang;LIU Jing;DAI Yan;YANG Feng;CHEN Li(School of Materials and Architectural Engineering,Guizhou Normal University,Guiyang 550025,China)

机构地区：[1]贵州师范大学材料与建筑工程学院,贵阳550025

出　　处：《表面技术》2023年第10期171-180,共10页Surface Technology

基　　金：黔科合基础(ZK[2023]-250);贵州省教育厅滚动支持省属高校科研平台项目黔教技([2022]012);贵州省研究生科研基金立项课题项目黔教合(YJSKYJJ[2021]100)。

摘　　要：目的 针对钛合金硬度低、耐磨性差的问题,利用机械球磨技术在TA1钛合金表面获得复合强化层,研究强化层的组织结构对合金磨损行为的影响。方法 采用行星式机械球磨装置,以WC粉末为增强介质,在0.05 MPa氮气气氛、转速为350 r/min、时间为8 h的条件下,对TA1钛合金进行表面机械变形+固相涂层复合强化处理,利用光学3D轮廓仪、XRD、SEM-EDS、往复式磨损机等对复合强化层的组织结构和耐磨性能进行测试。结果 当表层机械复合强化后,TA1钛合金表面的复合强化层由WC涂层+形变细晶区组成,硬化区厚度为20~40μm,形变细晶区厚度约为30μm。涂层区硬度达到1 100HV0.25,为基材硬度的5倍。在5 N载荷下,摩擦因数为0.2~0.3,并可保持近4 000 s,在10 N载荷下,摩擦因数接近0.2并可保持1 200 s。可将磨损过程分为低摩擦因数区、过渡区和高摩擦因数区3个阶段,且每阶段的磨痕深度、磨损量与摩擦因数具有正相关性。结论 表层机械复合强化可大幅提升TA1钛合金表层的硬度和耐磨性,WC颗粒增强涂层具有较强的减摩效果,其磨损机制主要是磨粒磨损与氧化磨损。这种一步法表面强化技术具有工艺简单、能耗少、涂层选材灵活的优势。Surface mechanical composite strengthening is a one-step surface modification technology with simple process,low energy consumption and flexible coating material selection.It can improve the surface properties of TA1 titanium alloy,such as hardness and wear resistance.Through high-speed movement of the grinding ball on the surface of the TA1 specimen,the impact and friction was repeated,which caused plastic deformation and gradual work hardening of the surface layer of the TA1 titanium alloy substrate.With the action of grinding ball,the surface grain size of dislocation was further mechanically induced by product and even tangles,which gradually lead to the formation of sub-grain boundaries and even amorphization,and thus lead to elaboration and strengthening,and the formation of a reinforcement layer of certain thickness.In addition,a small amount of added WC powder made the powder be repeatedly extruded and deformed at high speed impact of the grinding ball,and produced cold welding and mechanical coating on the surface of TA1 titanium alloy,thus forming the coating and further strengthening the effect.The material used in this experiment was TA1 titanium alloy,and the sample was Φ15 mm×8mm columnar material.A planetary mechanical ball milling device,zirconia ball milling tank and stainless steel ball were used to strengthen the TA1 titanium alloy surface by mechanical deformation and solid-phase coating at 0.05 MPa nitrogen atmosphere and 350 r/min speed for 8 h with WC powder as the reinforcing medium.Testing methods,such as Vickers hardness tester,optical 3D profilometer,XRD,SEM-EDS,and reciprocating wear machine were used to test and characterize the structure and wear resistance of the composite reinforced layer.The surface roughness of TA1 increased obviously.After mechanical strengthening,the composite strengthening layer of TA1 titanium alloy was composed of WC coating+deformed fine grain region.The thickness of the hardened layer was about 20-40 μm,and the structure was compact and uniform.The thic

关 键 词：TA1钛合金 机械形变 WC颗粒增强 复合强化层 摩擦磨损 

分 类 号：TG17[金属学及工艺—金属表面处理]