报告题目：Elements of bridging force intensity and scale in micro-wire de-bonding and toughening of metal reinforced ceramic matrix composites with inter-penetrating microstructures
报告时间：2012年6月12日,下午2:30
报告地点：材料系曹光彪楼326会议室
联系人：高明霞副教授
报告摘要：
Crack tip bridging by ductile ligaments and the corresponding work of deformation are essential in explaining the increasing of toughness, rupture strength and improve mechanical reliability of the composites. The methods of linear elastic fracture mechanics are applied in the analysis of the mechanical behavior of the composites with interpenetrating microstructures of a rigid ceramic skeleton and the thin filamentary shapes of ductile phase that fills in the nearly cylindrical spaces between ceramic grains. The effects of metal volume fraction, metallic phase ductility and dimensional scale of space filled by the metallic phase are accounted for.
The dependences of the short-crack toughness, asymptotic values of fracture toughness and the crack growth resistance of the composites are being investigated and values of the tear modulus and constant of the power law of the R-curve of fracture toughness were correlated to metal volume fraction, to pore /metal wire radius and topology found in the inter-penetrating microstructures. The effects of surface finishing and processing defects on the 3-P and 4-P bending strength are further discussed in relation to the trends of the R-curve of fracture toughness of the melt infiltrated composites.
报告人简介：
Dr. Joaquim M. Vieira, Professor, Materials Science and Engineering of the University of Aveiro. He graduated from Physics in 1976 and obtained his PhD in Ceramics from the University of Leeds (UK) in 1981. Since the beginning of his career he worked for the University of Aveiro in the domain of ceramics, glasses and composite materials. He cofounded CICECO- the Research Center for Ceramics and Composites Materials, a state-associated Laboratory, and became its Deputy Director, in 2002. He has developed extensive work in the fields of advanced ceramics, processing of composites and thin film deposition by a-MOCVD and RF-magnetron PVD. Themes of more recent research in partnerships include processing and mechanical evaluation of melt-infiltrated structural composites, magnetoresistive oxides, magnetocaloric oxides and multiferroics. Eu and Er doped La-Ca/Sr manganite fibers and Bi-Co oxide materials grown by laser floating zone are being studied for their magnetic, magnetocaloric and thermoelectric potentials. He published near one hundred scientific papers mostly in renowned international scientific journals and is committed to procurement of R & D and technology transfer with/to the companies trough the Technology Transfer Interface of CICECO.
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云顶yd222线路检测材料科学与工程学系
金属材料研究所
2012.06.08
