材料科学与工程导论双语课件教学课件 ppt 作者 陈克正 王玮 刘春延 等编Chapter 6.pptVIP

College of Materials Science and Engineering INTRODUCTION TO MATERIALS SCIENCE AND ENGINEERING Qingdao University of Science Technology Kezheng Chen Wei Wang Chunting Liu 国家级双语教学示范课程 ISSUES TO ADDRESS... CHAPTER 6 COMPOSITE MATERIALS ? What are the classes and types of composites? ? Why are composites used instead of metals, ceramics, or polymers? ? How do we estimate composite stiffness strength? ? What are some typical applications? metal polymer ceramic Matrix: The continuous phase Purpose is to: transfer stress to other phases; protect phases from environment Classification: MMC, CMC, PMC Composites: Multiphase materials Dispersed phase: Purpose: enhance matrix properties. MMC: increase sy, TS, creep resist. CMC: increase Kc PMC: increase E, sy, TS, creep resist. Classification: Particle, fiber, structural 6.1 Introduction Classification of Composites 6.2 Particle-Reinforced Composites Disperseion-strengthenend composites Particle-matrix interactions occur on the atomic or molecular level Strengthening is retained at elevated T and for extended time periods Large-Particle Composites “large”—— particle-matrix interactions cannot be treated on the atomic or molecular level The particulate phase is harder and stiffer than the matrix Utilized with all 3 material types 6.3 Fiber-Reinforced Composites Design goals: improved strength, smaller gravity The probability of the presence of a critical surface flaw that can lead to fracture diminishes with decreasing specimen volume. Fiber Phase Description of the contents Matrix Phase Wiskers Fibers Wires Metals Ceramics Polymers Description of the contents very thin single crystals crystalline perfection exceptionally high strengths Whiskers Fibers Wires polycrystalline or amorphous either polymers or ceramics have relatively large diameters typical materials: steel, Mo, W grouped into three different classifications Fiber Phase Matrix Phase Functi