TC4钛合金宽幅厚板材组织结构、织构及疲劳性能研究
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摘要
针对工业化生产工艺条件下的TC4钛合金宽幅、厚板材(δ150 mm),研究了板材边部、1/4板厚和心部位置微观组织结构、织构分布特点、疲劳性能及其疲劳断口特征。结果表明:TC4厚板材不同部位显微组织呈现初生α相+β转的双态组织形貌,由边部到心部,初生α相由等轴趋于等轴+条状形态,相比较边部,越靠近中心,初生α相形态趋于平行于轧面且初生α相尺寸相对较大;同一板厚不同位置α相微区织构明显不同,边部主要含有{3213}、{2130}弱织构组分,1/4板厚位置主要含有{0221}、{1011}和{1215}织构组分,心部主要含有{1100}、{1010}和{1430}强织构组分;板材边部疲劳极限为605 MPa、1/4板厚位置疲劳极限为440 MPa、心部疲劳极限为440 MPa。板材边部位置疲劳性能明显优于1/4板厚位置和心部位置,疲劳极限相差约165 MPa。疲劳试样断口由裂纹源区Ⅰ、裂纹扩展区Ⅱ和瞬断区Ⅲ3个不同区域组成。随着应力强度的降低,裂纹扩展区面积呈逐渐增加的规律。
For TC4 titanium alloy wide and thick plate(δ150mm) under industrial production process, the microstructure,texture distribution, fatigue properties and fatigue fracture characteristics of TC4 titanium alloy at the position of the edge, 1/4thickness position and center of wide thick plate(δ150mm) were studied. The results show that the microstructure of TC4 thick plate in different parts shows the binary structure of primary α phase and β transformation microstructure. Moreover,from the edge to the center of plate primary the α phase tends to be equiaxed and strip shape from equiaxed. Compared with the edge of plate, the morphology of primary, the α phase tends to be parallel to the rolling surface, and the size of primary αphase is relatively large. Meanwhile, the micro texture of α phase is obviously different in different position of plate with the same thickness. The main texture components are {3213} and {2130} weak texture in edge, {0221}, {1011} and {1215} texture in 1/4 thickness position, while {1100}, {1010} and {1430} strong texture in the center position of plate thickness. The fatigue limits are 605 MPa in edge, 440 MPa in 1/4 thickness position, and 440 MPa in the center position of plate. Compared with that of 1/4 thickness and center position, the fatigue performance of the edge of the plate is obviously better, the difference of fatigue limit is about 165 MPa. The fracture of the fatigue specimen is composed of three different regions, including crack source area I, crack growth area II and transient fault area III. With the decrease of stress intensity, the area of crack propagation presents a gradual increasing rule.
For TC4 titanium alloy wide and thick plate(δ150mm) under industrial production process, the microstructure,texture distribution, fatigue properties and fatigue fracture characteristics of TC4 titanium alloy at the position of the edge, 1/4thickness position and center of wide thick plate(δ150mm) were studied. The results show that the microstructure of TC4 thick plate in different parts shows the binary structure of primary α phase and β transformation microstructure. Moreover,from the edge to the center of plate primary the α phase tends to be equiaxed and strip shape from equiaxed. Compared with the edge of plate, the morphology of primary, the α phase tends to be parallel to the rolling surface, and the size of primary αphase is relatively large. Meanwhile, the micro texture of α phase is obviously different in different position of plate with the same thickness. The main texture components are {3213} and {2130} weak texture in edge, {0221}, {1011} and {1215} texture in 1/4 thickness position, while {1100}, {1010} and {1430} strong texture in the center position of plate thickness. The fatigue limits are 605 MPa in edge, 440 MPa in 1/4 thickness position, and 440 MPa in the center position of plate. Compared with that of 1/4 thickness and center position, the fatigue performance of the edge of the plate is obviously better, the difference of fatigue limit is about 165 MPa. The fracture of the fatigue specimen is composed of three different regions, including crack source area I, crack growth area II and transient fault area III. With the decrease of stress intensity, the area of crack propagation presents a gradual increasing rule.
引文
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[3]王韦琪,祝瀑,王俭,等.Ti-6A1-4V厚板研制[J].金属学报,2002,38(增刊1):389-391.
[4] Lu Bin, Yang Rui.Microstructure evolution of extruded Mg-Gd-Y magnesium alloy under dynamic compression[J]. Aerospace Materials Technology,2007,6:77-83.
[5]《稀有金属加工手册》编辑组.稀有金属加工手册[M].北京:冶金工业出版社,1984.
[6]杨建朝,王兴,谢英杰,等.大规格TC4钛合金厚板研制[J].钛工业进展,2014,31(3):22-25.
[7] Ding R, Guo Z X.Microstrctural evolution of a Ti6A14V alloy during phase processing:Experimental and simulation investigate[J].Material Science and Engieering A,2003,365(2):172-179.
[8] Sia Nemat, Guo Weiguo, Nesterenko Vitali F. Dynamic response of conventional and hot isostatieally pressed Ti-6Al4V alloys:experiments and modeling[J]. Mechanics of Materials,2001,31(4):425-439.
[9] Lee Woei Shyan, Liu Chefeng. High temperature deformation of Ti6A14V alloy evolution by high strain rate compression tests[J]. Journal of Material Processing Technology,1998,25(1):127-136.
[10] Li G A, Zhen L, C Lin, et a1.Deformation localization and recrystallization i n TC4 alloy under impact condition[J].Materials Science and Engineering,2005,395(1/2):98-l01.