Ti575合金动态力学性能和绝热剪切行为研究  

Dynamic Mechanical Properties and Adiabatic Shear Behavior of Ti575 Alloys

作　　者：王怡蕾 唐斌[1] 戴锦华 王慧琴 王毅 李金山[1] WANG Yilei;TANG Bin;DAI Jinhua;WANG Huiqin;WANG Yi;LI Jinshan(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,陕西西安710072

出　　处：《铸造技术》2025年第2期110-119,共10页Foundry Technology

基　　金：国家重点研发计划(2021YFB3702603)。

摘　　要：基于兵器领域对轻质抗冲击材料的现实需求,以具备高强度-塑性-冲击韧性匹配的Ti575合金为研究对象,通过热处理在Ti575合金中调控出三态组织和魏氏组织,并利用霍普金森压杆技术在3500 s^(-1)应变速率下开展动态力学性能测试,结合扫描电子显微镜对微观组织演化进行分析,揭示Ti575合金在高应变速率下的变形行为和响应机制,从而为后续研究提供指导意义。研究结果表明,Ti575合金不同组织状态下的高应变速率变形行为均分为弹性阶段、应变硬化阶段、稳定软化阶段和不稳定软化阶段4个阶段。动态压缩结果表明,三态组织冲击吸收功高于魏氏组织(三态组织:228 J/cm^(3);魏氏组织:200 J/cm^(3)),呈现出优于魏氏组织的动态力学性能。此外,经高应变速率变形后,两种组织均呈现绝热剪切失效特征。三态组织较魏氏组织而言,绝热剪切带数量少、宽度大,表明三态组织具有低于魏氏组织的绝热剪切敏感性,而三态组织较低的绝热剪切敏感性是其动态力学性能优于魏氏组织的主要原因。进一步断裂机制研究表明,不同组织Ti575合金经高应变速率变形后的断口形貌均由韧窝区和平滑区组成,高倍SEM观察表明两种组织均以韧性断裂机制为主,同时存在典型的剪切断裂特征。On the basis of the realistic demand for lightweight impact-resistant materials in weaponry,a Ti575 alloy,which possesses high strength-plasticity-impact toughness matching,was taken as the object of this research.Ti575 alloys with trimodal and widmanstatten microstructures were prepared through heat treatment,and dynamic mechanical property tests were carried out at a strain rate of 3500 s^(-1) via the Hopkinson pressure bar technique combined with microstructural evolution analysis by scanning electron microscopy observations.This study aims to reveal the deformation behavior and response mechanisms of Ti575 alloys through these tests,thereby providing guidance for subsequent research.The results indicate that the high strain rate deformation behavior of the Ti575 alloy with these two different microstructures can be divided into four stages:the elastic stage,strain hardening stage,stable softening stage,and unstable softening stage.The results of the dynamic compression tests reveal that the trimodal microstructure results in greater impact absorption energy than does the widmanstatten microstructure(trimodal microstructure:228 J/cm^(3);widmanstatten microstructure:200 J/cm^(3)),demonstrating better dynamic mechanical properties of the trimodal structure than that of the widmanstatten microstructure.Additionally,both microstructures display characteristics of adiabatic shear failure during high strain rate deformation.The characteristics of fewer and wider adiabatic shear bands in the trimodal microstructure suggest that it has lower sensitivity to adiabatic shear than the widmanstatten microstructure does,resulting in superior dynamic mechanical properties in the trimodal microstructure relative to the widmanstatten microstructure.Subsequent studies on the fracture mechanisms show that the fracture surfaces of the two microstructures of Ti575 alloys deformed at high strain rates consist of ductile dimple regions and smooth areas.Moreover,high-magnification SEM observations indicate that both microstructures p

关 键 词：Ti575钛合金 三态组织 魏氏组织 动态力学性能 绝热剪切 韧性断裂 

分 类 号：TG146.2[一般工业技术—材料科学与工程] TG113[金属学及工艺—金属材料]