Evaluating microstructural and damage effects in rule-of-mixtures predictions of the mechanical properties of Ni-Al2O3 composites
Evaluating microstructural and damage effects in rule-of-mixtures predictions of the mechanical properties of Ni-Al2O3 composites
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DOI：
10.1023/a:1004509220648
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发表时间：
1999-05-01
影响因子：
4.5
通讯作者：
Rabin, BH
中科院分区：
文献类型：
--
作者：
Bruck, HA;Rabin, BH
采用粉末加工技术制备了Ni含量为0 ~ 100 vol %的Ni-Al_2 O_3复合材料。通过改变金属：陶瓷颗粒的尺寸比，无论是颗粒增强或相互渗透相的显微组织得到。复合材料的力学性能进行了表征，并与规则的混合物（ROM）的预测进行比较。对于某些颗粒增强复合材料，超声波测量的弹性模量不服从ROM。这一结果是由于存在的损坏，可以使用现有的模型。在四点弯曲，大多数复合材料表现出线性弹性行为，但观察到显着的非弹性变形的复合材料含有60和80体积%的镍。使用ROM模型合理地描述了非弹性变形，除非存在实质性损伤。受损材料被建模为两相复合材料，其中包含一个无损伤相和一个完全受损相，假设其行为类似于多孔材料。采用半经验模型解释了含连续陶瓷相复合材料的破坏应变，该模型考虑了熔池损伤和残余应力的影响。使用新的ROM变形模型，根据预测的断裂应变计算断裂应力。为了更准确地描述韧性连续陶瓷复合材料的变形行为，对模型进行了修正，加入了约束效应。(C)1999 Kluwer Academic Publishers.
0Ni-Al2O3 composites containing 0 to 100 vol % Ni were fabricated using powder processing techniques. By varying the metal : ceramic particle size ratio, either particle-reinforced or interpenetrating-phase microstructures were obtained. The mechanical properties of the composites were characterized and compared with rule-of-mixtures (ROM) predictions. For certain particle-reinforced composites, the elastic moduli measured ultrasonically did not obey the ROM. This result was attributed to the presence of damage that could be accounted for using existing models. In four-point bending, most composites exhibited linear elastic behavior, however significant inelastic deformation was observed for composites containing 60 and 80 vol % Ni. The inelastic deformation was reasonably well described using ROM models, except when substantial damage was present. Damaged materials were modeled as two phase composites containing one damage-free phase and one completely damaged phase that was assumed to behave like a porous material. The failure strains of composites with continuous ceramic phases were explained using a semi-empirical model that included bath damage and residual stress effects. Fracture stresses were calculated from predicted fracture strains using a new ROM deformation model. The model was modified to include constraint effects in order to accurately describe the deformation behavior of the ductile continuous-ceramic composites. (C) 1999 Kluwer Academic Publishers.