1材料概论材料科学概论课件双语讲解.ppt

（4）聚合物时代 二战后各国致力于恢复经济，发展工农业生产，对材料提出了质量轻、强度高、价格低等一系列要求。具有优良性能的工程塑料部分地代替了金属材料。合成高分子材料的问世是材料发展的重大突破，从此以金属材料、陶瓷材料、高分子材料为主体，建立了完整的材料体系，形成了材料科学。 Polymeric Biomaterials Atrifical Heart Artifical Bone Composite materials: are constituted by two or more different materials, have specific properties. glass fiber reinforced resins: lightweight composites with high mechanical strength concrete: an agglomeration of cement, sand and gravel Classification: ceramics - ionic bonding covalent bonding Types of materials Metals and their alloys: are good conductors of heat and electricity; are opaque to visible light; are hard, rigid; can undergo plastic deformation have a high melting temperature (Tm). Organic polymers: made up of long-chain molecules; are electrical and thermal insulators; are light and easily formable; and the best-known organic polymers are: － poly (vinyl chloride) (PVC); － polyethylene (PE); － polystyrene (PS). Ceramics/inorganic nonmetallic materials: the combination of metallic elements (Mg, Al, Ti, ...) with non-metallic elements (o); have high mechanical and thermal resistance at high temperature; are very hard and used as abrasives; are electrical and thermal insulators; but some are thermal conductors, or semiconductors. 1.1.3 Properties Mechanical properties: the behavior of materials deformed by a set of forces. 弹性 Elasticity 塑性 Plasticity 强度 Strength 硬度 Hardness 韧性 Toughness 疲劳特性 Fatigue behaviour 耐磨性 Abrasion resistance Physical properties: the behavior of materials subjected to the action of temperature, electric or magnetic fields, or light. 电性能 Electric properties 磁性能 Magnetic properties 热性能 Thermal properties 光性能 Optical properties Chemical properties: the behavior of material in a