Anisotropic Deformation and Damage in Aluminium 2198 T8 Sheets
Anisotropic Deformation and Damage in Aluminium 2198 T8 Sheets
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DOI：
10.1177/1056789508101916
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发表时间：
2010-03
影响因子：
4.2
通讯作者：
D. Steglich;H. Wafai;W. Brocks
中科院分区：
文献类型：
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作者：
D. Steglich;H. Wafai;W. Brocks
对2198铝合金薄板的变形和损伤机理进行了实验和数值研究。在光滑和u形缺口平面试件上进行了三种不同方向的力学试验。对材料的微观结构进行表征，以获得第二相面积含量、颗粒形貌和空隙体积分数。用扫描电子显微镜对不同试样的断口表面进行了检测。纵向和横向加载的光滑试样的断裂面呈倾斜，与加载方向的夹角约为45°。以45°方向加载的样品以平坦的方式失效。缺口试样呈v形断口。故障从缺口根部开始。结果表明，原生孔隙首先在金属间颗粒处产生。空洞的生长和破裂是由空洞区域之间的剪切破坏引起的。进行了有限元计算，模拟了与取向相关的变形和损伤行为。结合基于孔隙度的各向同性损伤模型的现象学屈服准则允许定量预测试样在不同三轴性下的破坏。变形和损伤演化的相互作用可以证明。这类金属材料的von Mises屈服准则的缺陷变得明显。
The deformation and damage mechanisms of sheets aluminium alloy 2198 are investigated experimentally and numerically. Mechanical tests in three different orientations are carried out on smooth and U-notched flat specimens. The material’s microstructure is characterized to obtain the second phase area content, the morphology of particles and the void volume fraction. The fracture surfaces of the different specimens are examined using scanning electron microscopy. Smooth specimens loaded in the longitudinal and transversal orientation exhibit a slanted fracture surface, which has an angle of about 45° with respect to the loading direction. Samples loaded in 45°-orientation fail in a flat manner. Notched specimens show a V-shaped fracture surface. Failure initiates here at the notch root. It is shown that primary voids are first initiated at intermetallic particles. Void growth is promoted and rupture is caused by shear failure between regions of cavities. Finite element calculations are performed to simulate the orientation-dependent deformation and damage behavior. A phenomenological yield criterion combined with a porosity-based isotropic damage model allows for the quantitative prediction of specimen’s failure for different triaxialities. An interaction of deformation and damage evolution can be demonstrated. The deficit of the von Mises yield criterion for this kind of metallic materials becomes evident.