增材制造Ti6Al4V钛合金的激波压缩状态方程与动态变形机理研究  

SHOCK COMPRESSION EQUATION OF STATE AND DYNAMIC DEFORMATION MECHANISM OF ADDITIVE MANUFACTURED Ti6Al4V TITANIUM ALLOY

作　　者：牛洋洋 李统 周文博 盛冬林 鄢阿敏 曹富华 陈艳 汪海英[1,2] 戴兰宏 Niu Yangyang;Li Tong;Zhou Wenbo;Sheng Donglin;Yan Amin;Cao Fuhua;Chen Yan;Wang Haiying;Dai Lanhong(State Key Laboratory of Nonlinear Mechanics,Institute of Mechanics,Chinese Academy of Sciences,Beijing 100190,China;School of Engineering Science,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院力学研究所非线性力学国家重点实验室,北京100190 [2]中国科学院大学工程科学学院,北京100049

出　　处：《力学学报》2023年第8期1673-1685,共13页Chinese Journal of Theoretical and Applied Mechanics

基　　金：国家自然科学基金(11988102,12172367);国家自然科学基金叶启孙科学基金(U2141204);爆炸科学与技术国家重点实验室开放课题(KFJJ23-03M)资助项目。

摘　　要：增材制造工艺具有快速成型、结构可控等优势,有广阔的应用前景,然而增材制造的合金材料的动态性能研究相对贫乏.文章针对在国防空天领域应用广泛的Ti6Al4V合金,选取增材制造与锻造Ti6Al4V钛合金为研究对象,利用一级轻气炮系统,对两种不同工艺的钛合金材料开展不同冲击速度的平板撞击实验,同时借助光子多普勒测速(PDV)系统与阻抗匹配技术获得自由表面的粒子速度和激波速度,进而得到两种钛合金的Hugoniot状态方程.进一步,对变形样品微结构开展透射电镜(TEM)和电子背散射衍射(EBSD)表征,揭示其动态变形机理.发现两种合金都具有很高的相变阈值(锻造合金>7.90 GPa,增材制造合金>7.87 GPa)与冲击弹性极限HEL(锻造合金为2.56 GPa,增材制造合金为2.78 GPa),两种Ti6Al4V合金的塑性变形机理均为位错滑移主控,锻造合金在变形后期产生滑移带,增材制造合金的片层状α相与β相的相界面起着阻碍位错运动的强化作用,在变形后期位错线从α相中越过相界面滑移至相邻的另一个α相中,位错滑移越过相界面需要较大的应力输入,因此表现出相比锻造合金更高的冲击弹性极限HEL.The additive manufacturing(AM)process has the advantages of rapid prototyping and controllable structure,and has broad application prospects.However,the research on the dynamic properties of alloy materials manufactured by additive manufacturing is far from adequate.Due to the wide application of Ti6Al4V alloy in the field of national defense and aerospace,in this paper,the additive manufactured and forged Ti6Al4V titanium alloy was studied.The plate impact experiment with different impact velocities was carried out on two kinds of titanium alloys by using the one-stage light gas gun system.In the impact experiment,the particle velocity and the shock wave velocity of the free surface were obtained by means of the photon Doppler velocimetry(PDV)system and the impedance matching technology.The Hugoniot equation of state of the two titanium alloys was established.Furthermore,to reveal the dynamic deformation mechanism of alloys,transmission electron microscopy(TEM)and electron back-scattering diffraction(EBSD)were conducted to characterize the microstructure of the deformed samples.Both alloys were found to have high phase transformation thresholds(>7.90 GPa for forged alloys and >7.87 GPa for additively manufactured alloys)and high Hugoniot elastic limit HEL(2.56 GPa for forged alloys and 2.78 GPa for additively manufactured alloys).Both the plastic deformation mechanism of the Ti6Al4V alloys is mainly controlled by dislocation slip.The forged alloy produces slip bands in the late deformation stage.The phase interface between the lamellarαphase andβphase of the additively manufactured alloy acts as a reinforcement that hinders dislocation movement in the later stage of deformation,then the dislocation line slips from theαphase across the phase interface to another adjacentαphase,and the dislocation slip across the phase interface requires a larger stress input,which results in higher HEL value than that the forged alloy.

关 键 词：增材制造 TI6AL4V合金 冲击压缩 Hugoniot状态方程 变形机理 

分 类 号：O347[理学—固体力学]