Fatigue Crack Growth Mechanisms in Titanium Single Crystals

钛单晶的疲劳裂纹扩展机制

• 批准号: 09650767
• 负责人: TAKASHIMA Kazuki
• 金额: $ 2.18万
• 依托单位: TOKYO INSTITUTE OF TECHNOLOGY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09650767/
• 关键词: Titanium; Single Crystal; Fatigue; Crystallographic Orientation; Crack Growth Rate; Crack Growth Mechanism; Slip System; Twinning

The fatigue crack growth behavior of alpha-titanium single crystals has been investigated in laboratory air at room temperature. Six types of CT specimens A, B, C, D, E and F with different notch orientations were prepared. The notch plane and direction in the A-specimen were (1210) and [1010], and those in the B-specimen were (0110) and [2110], respectively. The notch plane of the C-specimen was (0110) and that of the D-specimen was (1210), and the notch direction of both the C- and the D-specimens was [0001], In the E- and the F-specimens, the notch plane was (0001), and the notch directions were [1010] and [2110], respectively. The crack in the A- and the B-specimens propagates parallel to (0110) [2110]. Therefore, the crack is deduced to extend by alternating shear on two intersecting prismatic slip systems at the crack tip. The crack in the C- and the D-specimens propagates close to the basal plane which is perpendicular to the notch directions. This indicates that the fatigue crack is difficult to grow along [0001] compared with parallel to the basal plane. In the E- and the F-specimens, the crack propagates roughly parallel to the basal plane and the traces which correspond to {1012} twin systems are found near the crack plane. Ridges parallel to <1010>, and traces and bands due to {1012} twinning are observed on the fatigue surfaces. These results suggest that the crack growth might occur plausibly by the activation of micro-twins. A definite crystallographic dependence of fatigue crack growth behavior in alpha-titanium is obtained.

本文研究了α-钛单晶在室温空气中的疲劳裂纹扩展行为。制备了A、B、C、D、E和F六种不同切口方向的CT标本。A试样的缺口平面和方向分别为（1210）和[1010]，B试样的缺口平面和方向分别为（0110）和[2110]。C试样的缺口平面为（0110），D试样的缺口平面为（1210），缺口方向均为[0001]; E试样的缺口平面为（0001），缺口方向分别为[1010]和[2110]。A和B样本中的裂纹平行于（0110）[2110]扩展。因此，裂纹扩展是由两个相交的棱柱滑移系在裂纹尖端的交替剪切。在C-和D-试样中的裂纹扩展接近基面垂直于缺口方向。这表明，与平行于基面相比，疲劳裂纹难以沿着[0001]扩展。在E-和F-试样中，裂纹大致平行于基面扩展，并在裂纹面附近发现对应于{1012}孪晶系统的痕迹。在<1010>疲劳表面上观察到平行于{1012}孪晶的脊、痕迹和条带。这些结果表明，裂纹扩展可能是由于微孪晶的激活而发生的。获得了α-钛疲劳裂纹扩展行为的晶体学依赖性。

项目成果

K.Takashima et al.: "Fatigue Crack Propagation in Titanium Single Crystals" Key Engineering Materials. 145-149. 721-726 (1998)

K.Takashima等：“钛单晶中的疲劳裂纹扩展”关键工程材料。

Y.Mine, T.Yamada, S.Ando, K.Takashima, H.Tonda, Y.Higo and P.Bowen: "Fatigue Crack Growth in Titanium Single Crystals" Key Eng.Materials. 145-149. 721-726 (1998)

Y.Mine、T.Yamada、S.Ando、K.Takashima、H.Tonda、Y.Higo 和 P.Bowen：“钛单晶中的疲劳裂纹生长”关键工程材料。

K.Takashima et al.: "Molecular Dynamics Simulation of Crack Propagation in a-Titanium Single Crystals" Modeling and Simulation Based Engineering. 2. 1227-1231 (1998)

K.Takashima 等人：“a-钛单晶中裂纹扩展的分子动力学模拟”基于建模和仿真的工程。

K.Takashima, Y.Mine, S.Ando, H.Tonda, Y.Higo and P.Bowen: "Effects of Crystallographic Oriniation on Fatigue Crack Growth in alpha-Titanium Single Crystals" Advances in Fracture Research. 3. 1645-1652 (1997)

K.Takashima、Y.Mine、S.Ando、H.Tonda、Y.Higo 和 P.Bowen：“晶体取向对 α-钛单晶疲劳裂纹扩展的影响”断裂研究进展。

高島 和希 他: "チタン単結晶における疲労き裂伝播の結晶方位依存性" 日本金属学会誌. 62. 708-717 (1998)

Kazuki Takashima 等人：“钛单晶中疲劳裂纹扩展的晶体取向依赖性”日本金属学会杂志 62. 708-717 (1998)。