双语课件聚合物科学与工程导论课件.ppt

Our Classification Scheme for Composite Materials Metal Matrix Composites (MMCs) ? mixtures of ceramics and metals, such as cemented carbides（烧结碳化物） and other cermets(金属陶瓷） Ceramic Matrix Composites (CMCs) ? Al2O3 and SiC imbedded with fibers to improve properties, especially in high temperature applications The least common composite matrix Polymer Matrix Composites (PMCs) ? thermosetting resins are widely used in PMCs Examples: epoxy and polyester with fiber reinforcement, and phenolic with powders Functions of the Matrix Material (Primary Phase) Provides the bulk form of the part or product made of the composite material Holds the imbedded phase in place, usually enclosing（封闭的） and often concealing（隐藏的） it When a load is applied, the matrix shares the load with the secondary phase, in some cases deforming so that the stress is essentially born （bear) by the reinforcing agent The Reinforcing Phase (Secondary Phase) Function is to reinforce the primary phase Imbedded phase is most commonly one of the following shapes: Fibers Particles Flakes In addition, the secondary phase can take the form of an infiltrated (渗透） phase in a skeletal or porous（多孔） matrix Example: a powder metallurgy（冶金）part infiltrated with polymer Fiber Orientation – Three Cases One?dimensional reinforcement, in which maximum strength and stiffness are obtained in the direction of the fiber Planar （平面的）reinforcement, in some cases in the form of a two?dimensional woven（weave编织） fabric Random or three?dimensional in which the composite material tends to possess isotropic properties Materials for Fibers Fiber materials in fiber?reinforced composites: Glass – most widely used filament Carbon – high elastic modulus Boron（硼） – very high elastic modulus Polymers – Kevlar （美国杜邦（Dupont）公司研制的一种芳纶纤维材料的商品名称，材料原名叫”聚对苯二甲酰对苯二胺“） Ceramics – SiC and Al2O3 Metals - steel The most important commercial use of fibers is in polymer composites Particles and Flakes A second common shape of imbedded pha