Research on Behavior of Tensile-torsional Fatigue of Ti6321 Alloy
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摘要: 通过Ti6321合金的拉-扭疲劳试验,对0°和30°相位差的疲劳寿命进行对比分析,研究0°相位差时微裂纹和宏观裂纹扩展路径,并对疲劳断口进行分析。结果表明:相同Mises等效应力幅下,相位差为30°时疲劳寿命相对相位差为0°时的较低;受切应力主要作用,Ti6321合金表面萌生的微裂纹绝大部分分布在与试样轴向夹角20°~30°范围内,且随着等效应力幅增大,拉扭疲劳试样外表面萌生的微裂纹数量也随之增多,主裂纹在扩展过程中与这些微裂纹合并,使得其尖端发生与试样轴向呈小夹角方向急转弯,抑制了其向沿大夹角方向的最大正应力所在平面方向扩展的趋势,从而影响了宏观裂纹的扩展面角度;拉扭疲劳主裂纹在扩展过程中留下了明显的台阶状形貌,这是由于主裂纹在扩展过程中通过此区域时,各界面微裂纹扩展情况不同而造成的。Abstract: The fatigue life of Ti6321 alloy with phase differences of 0°and 30°is analyzed by tensile-torsional fatigue test. The propagation path of micro-cracks and macro-cracks at 0°phase difference is studied, and the fatigue fracture surface analyzed.Resultsshow that axial-torsional fatigue life of Ti6321 alloy at 30° phase difference is shorter than that at 0° phase difference. The Ti6321 surface micro-cracks, mainly affected by shear stress, is initiated in the range of 20°~30° to axial direction. Besides, with the increase of equivalent stress amplitude, the number of initiated surface micro-cracks increases. And the main crack tip makes a sharp turn in the direction of small angle to axial direction due to the main crack and merges with micro-cracks during propagation, which restrains the main crack propagation along the maximum normal stress direction. The main axial-torsional fatigue crack, influenced by the micro-cracks, presents step morphology in the propagation zone.
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Keywords:
- Ti6321 alloy /
- tensile-torsional fatigue /
- phase difference /
- micro-crack /
- crack propagation plane
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[1] 钱江,王怡,李瑶.钛及钛合金在国外舰船上的应用[J].舰船科学技术,2016,38(11):1-6. [2] GERDL,JAMES C W.Titanium[M].Berlin:Springer Verlag,2003.
[3] 刘强,宋生印,李德君,等.钛合金油井管的耐腐蚀性能及应用研究进展[J].石油矿场机械,2014,43(12):88-94. [4] 史雪枝,周小虎.钛合金油井管性能研究及应用评价现状[J].钢管,2015,44(1):10-14. [5] JIANG Y Y,KURATH P.Nonproportional cyclic deformation:critical experiments and analytical modeling[J].International Journal of Plasticity,1997,13(8-9):743-763.
[6] ITOH T,YANG T.Material dependence of multiaxial low cycle fatigue lives under non-proportional loading[J].International Journal of Fatigue,2011,33(8):1025-1031.
[7] WU Z R,HU X T,SONG Y D.Multiaxial fatigue life prediction for titanium alloy TC4 under proportional and nonproportional loading[J].International Journal of Fatigue,2014,59:170-175.
[8] SUSMEL L,LAZZARIN P.A bi-parametric Wöhler curve for high cycle multiaxial fatigue assessment[J].Fatigue & Fracture of Engineering Materials & Structures,2002,25(1):63-78.
[9] HAN C,CHEN X,KIM K S.Evaluation of multiaxial fatigue criteria under irregular loading[J].International Journal of Fatigue,2002,24(9):913-922.
[10] KALLMEYER A R,KRGO A,KURATH P.Evaluation of multiaxial fatigue life prediction methodologies for Ti-6Al-4V[J].Journal of Engineering Materials and Technology,2002,124(2):229-237.
[11] PAPADOPOULOS I V,DAVOLI P,GORLA C,et al.A comparative study of multiaxial high-cycle fatigue criteria for metals[J].International Journal of Fatigue,1997,19(3):219-235.
[12] TROCHIDIS A,DOUKA E,POLYZOS B.Formation and evolution of persistent slip bands in metals[J].Journal of the Mechanics and Physics of Solids,2000,48(8):1761-1775.
[13] FORSYTH P J.A two stage process of fatigue crack growth[M].Cranfield:Crack Propagation Symp,1961:76-94.
[14] ENDO M,YANASE K.Crack path and threshold condition for small fatigue crack growth in annealed carbon steels under fully-reversed torsional loading[J].International Journal of Fatigue,2019,125:112-121.
[15] 孙训方,方孝淑,关来泰.材料力学-Ⅰ(5版)[M].北京:高等教育出版社,2009. [16] 陈亚军,王先超,王付胜,等.相位角加载条件下2A12铝合金多轴疲劳失效行为[J].材料导报,2017,31(14):147-152.
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