摘要
通常认为TB6钛合金中的β斑会降低构件的力学性能,Fe元素偏析是导致β斑的主要原因。利用OM、SEM、EDS、EPMA等微观表征手段,结合对β斑样品拉伸过程的扫描电镜原位观察,分析了β斑区域和正常区域的显微组织、化学成分和硬度差异,研究了β斑对TB6合金拉伸变形行为的影响。结果表明:β斑区域组织中的初生α相含量低于5%,β晶粒尺寸最大达到580μm,是正常晶粒尺寸的60倍以上;β斑区域的维氏硬度较正常区域略高;β斑区域中的V和Fe元素含量在宏观上无明显差异,但微区存在波动和不均匀分布,β斑区域的Fe元素含量离散性高于正常区域。V和Fe元素微区成分偏析是导致TB6合金后续加热和变形过程中相变温度差异的主要原因,局部先转变的β晶粒由于缺少晶界α相的钉扎,迅速长大。β斑材料在拉伸变形过程中,裂纹起始于粗大β晶粒的晶界处,晶界和晶内滑移是β斑组织的主要变形方式,含β斑的TB6合金的断裂模式为沿晶和穿晶混合的断裂模式。
It is generally believed that the"βfleck"in TB6 titanium alloy will reduce the mechanical properties of the component,and the main cause of theβfleck in TB6 alloy is Fe element segregation.In this research,the differences of microstructure,chemical composition and hardness betweenβfleck and normal area were analyzed by OM,SEM,EDS and EPMA,and the effect ofβfleck on the tensile deformation behavior of TB6 alloy was studied.The results show that the content of primary a phase inβfleck is less than 5%,and theβgrain size is coarse up to 580μm,which is more than 60 times of normal grain size.The Vickers hardness ofβfleck is slightly higher than that of normal area.The results of composition analysis show that there is no significant difference for V and Fe content betweenβfleck and normal area,but there are fluctuations and uneven distribution of Fe content within the microregions.Fe content dispersion inβfleck is higher than in normal area.The segregation of V and Fe elements in microregions is the main reason for the difference in the phase transition temperature of TB6 alloy during subsequent heating and deformation.The preconvertedβgrains grow rapidly due to the lack of pinning by grain boundary a phase.In the process of in situ tension,the crack starts at the grain boundary of the coarseβgrain,and grain boundary and intra-crystal slip are the main deformation modes ofβfleck structure.The fracture mode of TB6 alloy containingβfleck is intergranular and transgranular mixed fracture mode.
作者
史蒲英
刘向宏
李建伟
王凯旋
王涛
吴明
张丰收
何卫锋
Shi Puying;Liu Xianghong;Li Jianwei;Wang Kaixuan;Wang Tao;Wu Ming;Zhang Fengshou;He Weifeng(School of Mechanical Engineering,Xi'an Jiaotong University,Xi'an 710049,China;Western Superconducting Technologies Co.,Ltd,Xi'an 710018,China;Army Aviation Military Representative Office Stationed in Jingdezhen,Jingdezhen 333002,China)
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2023年第5期1925-1931,共7页
Rare Metal Materials and Engineering
基金
陕西省重点研发计划(2018ZDXM-GY-140)。
关键词
TB6钛合金
β斑
SEM原位拉伸
变形行为
沿晶和穿晶混合断裂模式
TB6 titanium alloy
βfleck
in situ SEM tensile
deformation behavior
intergranular and transgranular mixed fracture modes
