Experimental and numerical investigations of the effects of the spatial distribution of α phase on fracture behavior in hypoeutectic Al-Si alloys
Experimental and numerical investigations of the effects of the spatial distribution of α phase on fracture behavior in hypoeutectic Al-Si alloys
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DOI：
10.1016/j.actamat.2006.06.036
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发表时间：
2006-10
期刊：
影响因子：
9.4
通讯作者：
L. Qian;H. Toda;S. Nishido;Toshiro Kobayashi
中科院分区：
文献类型：
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作者：
L. Qian;H. Toda;S. Nishido;Toshiro Kobayashi
均匀、细小的α相组织提高了Al-Si合金的力学性能，但α相对裂纹扩展行为的影响仍是一个悬而未决的问题。研究了不同显微组织的双相Al-7% Si合金中α相的形态和分布对断裂行为的影响。利用原位实验研究了微观结构因素对裂纹扩展行为的影响。结果表明，球状α相组织产生直线裂纹扩展路径，而树枝状取向α相组织产生偏转裂纹扩展路径。进行有限元建模来模拟断裂行为，并使观察到的现象合理化。数值结果表明，由于α相和共晶相的弹塑性不匹配，α相的形态和分布改变了近端应力、应变和位移场的对称性和强度，对裂纹扩展方向和裂尖驱动力有重要影响.
A uniform, fine α phase microstructure enhances the mechanical properties of Al–Si alloys; however, it is an open question as to how the α phase affects the crack growth behavior. This paper addresses the effects of the morphology and distribution of α phase on the fracture behavior in a model dual-phase Al–7% Si alloy with different microstructures. The influences of microstructural factors on crack growth behavior are examined using in situ experiments. The results show that a globular α phase microstructure produces a straight crack growth path, whereas a dendritic, orientational α phase microstructure leads to a deflected crack profile. Finite-element modeling is performed to simulate the fracture behavior, and to rationalize the observed phenomena. The near-tip J-integral-based fracture criterion is used to predict the fracture path. Numerical results indicate that a variation in the morphology and distribution of α phase changes the symmetry and intensity of the near-tip stress, strain and displacement fields due to the strong mismatch in elastic–plastic properties of the α phase and eutectic phase, which have major influences on both crack growth direction and crack tip driving force.