Please wait a minute...
金属学报  2016, Vol. 52 Issue (5): 583-591    DOI: 10.11900/0412.1961.2015.00511
  论文 本期目录 | 过刊浏览 |
表面粗糙度对Ti-6Al-4V合金超高周疲劳性能的影响*
朱莉娜,邓彩艳(),王东坡,胡绳荪
天津大学材料科学与工程学院, 天津 300072
EFFECT OF SURFACE ROUGHNESS ON VERY HIGH CYCLE FATIGUE BEHAVIOR OF Ti-6Al-4V ALLOY
Lina ZHU,Caiyan DENG(),Dongpo WANG,Shengsun HU
School of Materials Science and Engineering, Tianjin University, Tianjin 300072, China
引用本文:

朱莉娜,邓彩艳,王东坡,胡绳荪. 表面粗糙度对Ti-6Al-4V合金超高周疲劳性能的影响*[J]. 金属学报, 2016, 52(5): 583-591.
Lina ZHU, Caiyan DENG, Dongpo WANG, Shengsun HU. EFFECT OF SURFACE ROUGHNESS ON VERY HIGH CYCLE FATIGUE BEHAVIOR OF Ti-6Al-4V ALLOY[J]. Acta Metall Sin, 2016, 52(5): 583-591.

全文: PDF(1271 KB)   HTML
摘要: 

采用自行研制的超声疲劳实验装置, 研究不同表面粗糙度下Ti-6Al-4V合金的超高周疲劳性能. 结果表明, 当表面凹痕宽深比a/c (a为凹痕宽度, c为凹痕深度)在2~10之间时, Ti-6Al-4V合金的临界凹痕深度在0.49~1.10 μm之间. 当表面凹痕深度小于临界深度时, 表面粗糙度对Ti-6Al-4V合金的超高周疲劳性能没有影响. 当表面凹痕深度大于临界深度时, Ti-6Al-4V合金疲劳寿命随表面粗糙度的增加而下降, 并且随着循环周次的增加, Ti-6Al-4V合金疲劳性能对表面粗糙度的敏感性下降. 随着表面粗糙度的增加, Ti-6Al-4V合金超高周疲劳裂纹的萌生方式发生变化. 超高周疲劳裂纹源有由一个向多个、由内部向次表面转移的趋势; 当表面凹痕深度增加到一定程度后, 在超高周疲劳寿命区间, Ti-6Al-4V合金疲劳寿命随粗糙度的增加而大幅下降. 疲劳裂纹全部从合金表面凹痕根部处萌生, 没有内部萌生的情况.

关键词 Ti-6Al-4V合金超高周疲劳表面粗糙度    
Abstract

Ti-6Al-4V alloys are widely used in aero engine blades for their unique properties, such as high specific strength, high specific stiffness and high fatigue strength. Aero engine blades usually suffer a variety of cyclic loading during the period of services, which finally results in fatigue failure. Fatigue life of materials is known to highly depend on the surface quality. Consequently, more and more researches about the influence of machined surface roughness on the fatigue behavior of materials have been carried out in the last decades. However, there are less relevant results about the relationship between surface roughness and very high cycle fatigue (VHCF) properties of Ti-6Al-4V alloy. To investigate the effects of surface roughness on fatigue properties of Ti-6Al-4V alloy under very high cycle fatigue regimes, ultrasonic fatigue tests were conducted at the conditions of 20 kHz and stress ratio R1=-1 at room temperature in air. During ultrasonic fatigue testing, each specimen was water-cooled. The specimen surfaces were cut and grinded which gave different surface roughnesses. The surface roughness was characterized using profilometry. In order to explain the high dependence of stress-fatigue life curves on the surface roughness, an approach based on the finite element analysis of measured surface topography was proposed. The results show that the VHCF property of Ti-6Al-4V alloy was significantly affected by surface roughness. The critical flaw size was 0.49~1.10 μm when the ratio between spacing and height of circumferential grooves was between 2~10. When surface roughness was smaller than the critical flaw size, surface roughness exerted no influence on fatigue life. While surface roughness was greater than critical flaw size, fatigue life decreased with increasing surface roughness. Surface roughness played a more important role in long life regime than that in VHCF regime in which with the growth of surface roughness, the crack initiation site changed from single one to two or more ones, as well as changed from inside to subsurface. When the surface roughness was large enough, all cracks initiated from surface even in super long life regime.

Key wordsTi-6Al-4V alloy    very high cycle fatigue    surface roughness
收稿日期: 2015-09-30     
基金资助:*国家自然科学基金资助项目51375331
图1  Ti-6Al-4V合金的显微组织
图2  Ti-6Al-4V合金中间等截面超声疲劳试件形貌与尺寸
图3  表面凹痕的形貌与尺寸
图4  带有表面凹痕的Ti-6Al-4V合金超声疲劳试件有限元模型
图5  Ti-6Al-4V疲劳试件的表面形貌及粗糙度
Sample Ra / μm Ry / μm
1 0.05 0.51
2 0.15 0.68
3 0.47 1.73
4 0.65 2.97
5 7.43 18.34
表1  Ti-6Al-4V合金试样的表面粗糙度
图6  不同表面粗糙度的Ti-6Al-4V合金进行超高周疲劳实验后的应力-疲劳寿命(σ-Nf)曲线
图7  Sample 1的超高周疲劳裂纹源形貌
图8  Sample 3的超高周疲劳裂纹源形貌
图9  Sample 4表面萌生裂纹的超高周疲劳裂纹源形貌
图10  Sample 5表面萌生裂纹的超高周疲劳裂纹源形貌
图11  Ti-6Al-4V合金超声疲劳试件表面凹痕附近的应力分布云图
图12  Ti-6Al-4V合金超声疲劳试件表面凹痕处的应力集中系数
图13  表面粗糙度对Ti-6Al-4V合金应力-疲劳寿命曲线和萌生位置的影响
Sample 2a / μm c / μm Calculated fatigue strength / MPa Modified fatigue strength / MPa Experimental fatigue strength / MPa
2 20 0.7 468.4 604.2 600
3 15 1.6 447.9 577.8 575
4 16 3.0 422.7 545.3 520
表2  Ti-6Al-4V合金疲劳强度的预测值、修正值与实验值的比较
[1] Liu C, Zhang J X, Wu B, Gong S L.Mater Des, 2012; 34: 609
[2] Wang S G, Wu X Q.Mater Des, 2012; 36: 663
[3] Lu W, Shi Y W, Lei Y P, Li X Y.Mater Des, 2012; 34: 509
[4] Stefanie S T.Int J Fatigue, 2014; 60: 17
[5] Suresh S.Fatigue of Materials. Cambridge: Cambridge University Press, 1998: 345
[6] Yuri T, OnoY, Ogata T.Cryogenics, 2006; 46: 30
[7] David B L, Theodore N, Anthony P.Int J Fatigue, 2005; 27: 1623
[8] Yamashita Y, Ueda Y, Kuroki H, Shinozaki M.Eng Fract Mech, 2010; 77: 1439
[9] Ren W, Nicholas T.Mater Sci Eng, 2003; A357: 141
[10] Suraratchai M, Limido J, Mabru C, Chieragatti R.Int J Fatigue, 2008; 30: 2119
[11] Arola D, Williams C L.Int J Fatigue, 2002; 24: 923
[12] Murakami Y, Endo M.Int J Fatigue, 1994; 16: 163
[13] Matikas T E.J Sound Vib, 2001; 247: 673
[14] Shimatani Y, Shiozawa K, Nakada T, Yoshimoto T, Lu L.Int J Fatigue, 2011; 33: 122
[15] Neal D F, Blenkinsop P A.Acta Metall, 1976; 24: 59
[16] Sinha V, Mills M, Williams J.Metall Mater Trans, 2006; 37: 2015
[17] Sushant K J, Christopher J S, Patrick J G.Int J Fatigue, 2012; 42: 248
[18] McEvily A J, Nakamura T, Oguma H, Yamashita K, Matsunagac H, Endo M.Scr Mater, 2008; 59: 1207
[19] Zuo J H, Wang Z G, Han E-H.Acta Metall Sin, 2007; 43: 705
[19] (左景辉, 王中光, 韩恩厚. 金属学报, 2007; 43: 705)
[20] Umezawa O, Nagai K.ISIJ Int, 1997; 37: 1170
[21] Sinha V, Mills M, Williams J.Metall Mater Trans, 2006; 37A: 2015
[22] Wardclose C M, Beevers C J.Metall Trans, 1980; 11A: 1007
[23] Bridier F, Villechaise P, Mendez J.Acta Mater, 2008; 56: 3951
[24] Bantounas I, Dye D, Lindley T C.Acta Mater, 2009; 57: 3584
[25] Siebel E, Gaier M.Trans Eng Digest, 1957; 18: 109
[1] 宋文硕, 宋竹满, 罗雪梅, 张广平, 张滨. 粗糙表面高强铝合金导线疲劳寿命预测[J]. 金属学报, 2022, 58(8): 1035-1043.
[2] 郭军力, 文光华, 符姣姣, 唐萍, 侯自兵, 谷少鹏. 冷却速率对包晶钢凝固过程中包晶转变收缩的影响[J]. 金属学报, 2019, 55(10): 1311-1318.
[3] 徐江, 鲍习科, 蒋书运. 纳米晶Ta2N涂层在模拟人体环境中的耐蚀性能研究[J]. 金属学报, 2018, 54(3): 443-456.
[4] 张亚娟, 王海滨, 宋晓艳, 聂祚仁. SLM球形Ni粉的制备与打印工艺性能[J]. 金属学报, 2018, 54(12): 1833-1842.
[5] 刘汉青, 何超, 黄志勇, 王清远. TC17合金超高周疲劳裂纹萌生机理[J]. 金属学报, 2017, 53(9): 1047-1054.
[6] 刘小龙,孙成奇,周砚田,洪友士. 微结构和应力比对Ti-6Al-4V高周和超高周疲劳行为的影响*[J]. 金属学报, 2016, 52(8): 923-930.
[7] 张金虎,徐东生,王云志,杨锐. 位错对Ti-6Al-4V合金α相形核及微织构形成的影响*[J]. 金属学报, 2016, 52(8): 905-915.
[8] 王彬,熊良银,刘实. 射频反应溅射制备MgO二次电子发射薄膜*[J]. 金属学报, 2016, 52(1): 10-16.
[9] 张永健 惠卫军 项金钟 董瀚 翁宇庆. 晶粒尺寸对42CrMoVNb钢超高周疲劳性能的影响[J]. 金属学报, 2009, 45(7): 880-886.
[10] 洪友士 赵爱国 钱桂安. 合金材料超高周疲劳行为的基本特征和影响因素[J]. 金属学报, 2009, 45(7): 769-780.
[11] 钱桂安 洪友士. 环境介质对40Cr结构钢高周和超高周疲劳行为的影响[J]. 金属学报, 2009, 45(11): 1356-1363.
[12] 李永德; 杨振国; 李守新; 柳洋波; 陈树铭 . GCr15轴承钢超高周疲劳性能与夹杂物相关性[J]. 金属学报, 2008, 44(8): 968-972 .
[13] 李永德; 李守新; 杨振国; 柳洋波; 翁宇庆; 惠卫军; 戎利建 . 氢对高强弹簧钢50CrV4超高周疲劳性能的影响[J]. 金属学报, 2008, 44(1): 64-68 .
[14] 左景辉; 王中光; 韩恩厚 . Ti-6Al-4V合金的超高周疲劳行为[J]. 金属学报, 2007, 43(7): 705-709 .
[15] 姚卫星; 郭盛杰 . LC4CS铝合金的超高周疲劳寿命分布[J]. 金属学报, 2007, 43(4): 399-403 .