指導教授：段維新臺灣大學：材料科學與工程學研究所侯鈞議Hou, Chun-YiChun-YiHou2014-11-262018-06-282014-11-262018-06-282014http://ntur.lib.ntu.edu.tw//handle/246246/262047由於碳化硼具有高硬度、高楊氏係數、高熔點以及低密度的性質，碳化硼被大量的運用於防彈衣、航太材料、中子吸收防護等工業用品中。而碳化硼所面臨的最大問題在於其難緻密性以及低韌性，金屬熔滲法為一有效的方式解決這兩個問題。由於鋁的低熔點以及低密度的特性，在不增加密度的前提下，製程溫度可大幅地降低，同時鋁的導入也可增加此複合物的韌性。 本研究將鋁矽混合粉熔滲進入多孔碳化硼之中，並探討熔滲溫度、熔滲時間以及矽添加對於相組成、微結構、機械性質以及熱傳導性質的影響。 結果顯示為製備緻密的複合材料，熔滲的溫度須高於1100oC。而熔滲溫度以及熔滲時間對於相組成有著顯著的影響，我們可以藉由控制熔滲的溫度以及熔滲的時間來控制複合材料中的相組成並進一步的決定複合材料的機械性質。在較低溫度進行熔滲的試樣會有較高的韌性以及強度，反之，試樣的硬度會隨著熔滲溫度的降低而減少。Due to the superb properties such as high hardness, low density, high melting point and high elastic modulus, boron carbide has been applied in armor, rocket, and neutron absorption layer. However, the usage of boron carbide is limited due to its high densification temperature and low fracture toughness. These problems can be coped with by adding metallic phase, such as aluminum. In the present study, the use of Al-12%Si mixed powders to infiltrate into porous B4C powder compacts is explored. The effect of infiltration temperature, time and the Si addition on the phase content, microstructure, mechanical properties and thermal conductivity is investigated. The results indicate that nearly fully dense composites can be manufactured through the infiltration technique. The infiltration temperature is higher than 1100oC. The phase content of composites depends strongly on the infiltration temperature and time. Both fracture toughness and flexural strength increase with the decrease of infiltration temperature. On the contrary, the hardness is decreased with the decrease of infiltration temperature.CHAPTER 1 INTRODUCTION 1 CHAPTER 2 LITERATURE SURVEY 3 2-1 Boron carbide (B4C) system 3 2-1-1 Structure of boron carbide 3 2-1-2 Properties of boron carbide 4 2-1-3 Synthesis of boron carbide 5 2-1-4 Densification of boron carbide 8 2-2 B4C/Al system 15 2-2-1 Wettability and infiltration 15 2-2-2 Reaction phases 17 2-2-3 Additive and mechanical properties 20 CHAPTER 3 EXPERIMENTAL PROCEDURES 27 3-1 Preparation of specimens 27 3-1-1 Materials 27 3-1-2 Infiltration process 27 3-1-3 Post treatment 28 3-2 Characterization of B4C/Al composites 31 3-2-1 Phase identification 31 3-2-2 Density measurement 31 3-2-3 Microstructure observation 31 3-2-5 Electron probe microanalysis 32 3-3 Mechanical properties measurement 32 3-3-1 Young’s modulus 32 3-3-2 Fracture toughness and hardness 33 3-3-3 Flexural strength 34 3-4 Thermal conductivity measurement 35 CHAPTER 4 RESULTS 36 4-1 Infiltration of Al-12%Si mixed into B4C 36 4-1-1 Specimens appearance and homogeneity of B4C/(Al,Si) composites 36 4-1-2 Phase identification 41 4-1-3 Microstructure observation 44 4-1-4 Density 46 4-1-5 Mechanical properties 57 4-1-6 Thermal conductivity 61 4-2 Infiltration of Al into B4C 62 4-2-1 Phase identification and microstructure observation 62 4-2-2 Mechanical properties 63 CHAPTER 5 DISCUSSION 67 5-1 Densification 67 5-2 Reaction phases 70 5-2-1 Effect of temperature 70 5-2-2 Effect of time 72 5-2-3 Addition of Si 73 5-3 Microstructure observation 75 5-4 Mechanical properties 78 5-5 Thermal conductivity 80 CHAPTER 6 CONCLUSIONS 83 REFERENCE 85 APPENDIX, PREPARATION OF B4C/SI COMPOSITES 94 I. Infiltration of Si into B4C 947467393 bytesapplication/pdf論文公開時間：2015/07/09論文使用權限：同意有償授權(權利金給回饋學校)碳化硼鋁熔滲法複合材料機械性質thesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/262047/1/ntu-103-R01527007-1.pdf