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TY  - THES
AU  - Chen, Geng
TI  - Strength prediction of particulate reinforced metal matrix composit
VL  - 12
PB  - RWTH Aachen University
VL  - Dissertation
CY  - Aachen
M1  - RWTH-2016-08542
SN  - 978-3-8440-4725-7
T2  - Werkstoffanwendungen im Maschinenbau
SP  - 1 Online-Ressource (206 Seiten) : Illustrationen, Diagramme
PY  - 2016
N1  - Auch veröffentlicht auf dem Publikationsserver der RWTH Aachen University
N1  - Dissertation, RWTH Aachen University, 2016
AB  - Particulate reinforced metal matrix composite (PRMMC) are made by dispersing reinforcement particles into a metal matrix and sintering. By optimizing the process parameters and the composition of the material, the major advantages of ceramics and metals can be combined and resulting in a material with high hardness, high wear resistance and sufficient toughness. When used as a structural material, failure of the PRMMCs are often caused by material deterioration accumulated over a large number of load cycles. As composed of two phases, PRMMCs can be regarded as mechanical systems on the mesoscale, therefore their overall responses are greatly influenced by the alignment of the reinforcement phase and the underlying material morphology. Understanding how the microstructure contributes to the global material behavior, above all the macroscopic strengths, is one of the central tasks of the thesis.In the present study, a numerically based methodology for determining the load bearing capacity of PRMMCs under both monotonic and cyclic loadings is presented. To evaluate the influence of the composite structure on the global behavior of PRMMCs, a multi scale approach which combines the shakedown analysis with homogenization was used. To take into account the randomness associated with the composite structure of the material, statistical methods have been applied to interpret the results. To prepare a sufficient number of representative volume element (RVE) models for the statistical study, a computational tool was developed to automate the generation of RVE samples. The general work flow of the established numerical approach can be summarized as follows: first, a large number of RVE was constructed as finite element models from either real or artificial material microstructures using the aforementioned in-house code. Next, lower and upper bound limit and shakedown problems were carried out by means of the interior-point method. Finally, results were converted to their corresponding macro quantities and evaluated statistically. With this approach a representative PRMMC material, WC/Co, was studied.Based on the established numerical work flow, ultimate strength and endurance limit of the material were predicted. The relationship between them and other material parameters, such as the effective Young’s modulus and the binder content was examined. The study investigated how the predicted strength is influenced by the RVE size and the size of reinforcement particles. The study also exposed the change of the feasible load domain, when the kinematic hardening of the binder phase is considered or when multiple independently varied loads are applied simultaneously. In addition to that, the study built predictive models and used them to explain, what are the decisive factors that determine the endurance limit of the overall composite material.
LB  - PUB:(DE-HGF)11 ; PUB:(DE-HGF)3
UR  - https://publications.rwth-aachen.de/record/673258
ER  -