。590 北京科技大学学报 第31卷 基体内部扩展.在两类裂纹交汇、撕裂过程中，裂纹 系合金组织和性能的影响.金属热处理，2005,47(7)：9) 尖端局部区域会发生一定的塑性变形，以协调裂纹 [6 Bae D H.Kim S H.Kim D H,et al.Deformation behavior of Mg-Zn-Y alloys reinfored by icosahedral quasicrystalline parti- 扩展方向，因此在断口表面出现撕裂棱. ds.Ac1Ma1e,2002.50:2343 [7 Bae D H.Lee M H.Kim K T,ct al.Applicat ion of quasicrystah 主裂纹 基体裂纹 ine particles as a strengthening phase in Mg-Zm Y alloys.J Alloys mpd.2002.342:445 [8 Kai YZ.Jie D.Wen JD.et al.Effect of RE content on the frac- 基体裂纹上撕裂分开 ture behavior in Mg-GdNdZr alloys.Mater Sci Forum,2007. 202(1):546 主裂纹 I9 Wu A R.Xia C Q.Gu Y,et al.Research of Mg RE alloy on mi- 图9。裂纹通过撕裂形成台阶的示意图 crostructure and properties.Heat Treat Met,2005.30(8):21 Fig.9 Schematic of forming a sidestep of cracks by tearing (吴安如，夏长清，古一，等.镁-稀土合金的显微组织和力学性 能研究.金属热处理，2005,30(8)：21) 10 LiuG Q.Chen L P.Ai Y L,et al.Infhence of Nd on mi- 4结论 crost ructu re and properties of ZM 5 alloys.Spec Cast Non ferrous (1)通过动态拉伸原位观察实验可知，当外加 41l@3,2005,25(7):496 (刘刚强，陈乐平，艾云龙，等.稀土Nd对ZM5合金组织与性 载荷超过1.176kN时，ZK60合金板缺口前端裂纹 能影响的研究.特种铸造及有色合金，2005,25(7)：496) 萌生，而ZK60(0.9Y)合金板材加载至1.273kN时 [11]Song M J.W ang Z X.Wang L Y.et al.Superplasticity and 缺口部位萌生裂纹. fractu re mechanism of A231B magnesium alloy sheet.Light A (2)ZK60和ZK60(0.9Y)合金板材宏观断口 loy Fabr Technol,2005,33(8):39 均有解理、准解理断裂痕迹，断口表面都出现小台阶 (宋美娟，王智样，汪凌云，等.AZ31B镁合金板材超塑性变形 与断裂机理研究.轻合金加工技术，2005,33(8)：39) 与撕裂岭：随着载荷增大，主裂纹与基体裂纹撕裂贯 [12]Ohr S M.An ekctron micmoscope study of crack tip deformation 通.ZK60合金中主裂纹扩展过程中出现分枝， and its impact on the disbeation theory of fracture.Mater Sci ZK60(0.9Y)合金主裂纹沿第2相扩展，未出现分 Eng,1985,72():1 枝，断口处出现褶皱，基体裂纹多萌生于破碎的第2 [13 Wang X S.Liang F,Zeng Y P,et al.SEM in situ observations 相附近. to the effects of inlusions on initiation and propagation of the low cyclic fatigue crack in super strength steel.Acta Metall Sim,2005,41(12):1272 参考文献 (王习术，梁锋，曾燕屏，等.夹杂物对超高强度钢低周疲劳裂 [1]Decker R F.The menaissance in magnesium.Adv Mater Proass- 纹萌生及扩展影响的原位观测.金属学报，2005,41(12)： ,1998.157(9):31 1272) [2]Froes F H,Aghion E,Elezer D,et al.The science technology and [14 Liang C L,Li X Y.Gong S L.et al.Im situ SEM observation applications of magnesium.Ady Perform Mater,1998,5(3): on fracture behavior of laser welded BT20 titanium alloy pints. 201 Rare Met Mater Eng,2006.35(12):1924 [3]Chen Z H.Wrought Magnesium Alloys.Beijing:Chemical In- (粱春雷，李晓延，巩水利，等.SEM原位观察BT20钛合金激 dustry Press 2005 光焊接头的膨裂行为.稀有金属材料与工程，2006,35(12)： (陈振华.变形镁合金.北京：化学工业出版社，2005) 1924) [4]Yu K.Li W X,Wang R C.et aL.Research,development and [15]Lu Y Z.Wang Q D.Ding W J.et al.Fracture behavior of application of wrought magnesium alloys.Chin J Nonferrous AZ91 magnesium alloy.Mater Lett,2000,44(5):265 Me,2003,13(2):277 16 Ha K F.Microsopic Theory of Metal Mechanical Properties. (余琨，黎文献，王日初，等.变形镁合金的研究、开发及应用.中 Beijing Science Press,1983 国有色金属学报，2003.13(2)：277) (哈宽富.金属力学性质的微观理论.北京：科学出版社， [5]Wang B.Yi D Q.Fang X Y.et al.Influence of Y and Nd on 1983) Miemstnucture and Pmoperies of Mg-Zn-Zr Alloys Heat Treat I 17]Bae D H.Kim D H,Kim W T,et al.High strength Mg-Zn-Y Me,2005,47(7):9 alloy contairing quasicrystalline particles.Mater Trans,2001. (王斌，易丹青，方西亚，等.稀土元素Y和Nd对Mg一Z一Zr 42(10):2144基体内部扩展.在两类裂纹交汇 、撕裂过程中, 裂纹 尖端局部区域会发生一定的塑性变形, 以协调裂纹 扩展方向, 因此在断口表面出现撕裂棱 . 图 9 裂纹通过撕裂形成台阶的示意图 Fig.9 S chematic of forming a sidestep of cracks by tearing 4 结论 (1) 通过动态拉伸原位观察实验可知, 当外加 载荷超过 1.176 kN 时, ZK60 合金板缺口前端裂纹 萌生, 而ZK60( 0.9Y) 合金板材加载至 1.273 kN 时 缺口部位萌生裂纹. 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