【作者】 王娜；

【导师】 李邦盛；

【作者基本信息】 哈尔滨工业大学 ， 材料加工工程， 2006， 硕士

【摘要】 本文以铜、硼和钛的单质粉末为原料,经混粉-冷压成形-真空电磁烧结-热压工艺,制备了原位自生纳米级TiB2陶瓷颗粒增强铜基复合材料。针对Ti-B-Cu体系,本文借助XRD和SEM分析,对TiB2/Cu复合材料的相组成和显微组织进行了研究,并通过液淬实验和差热分析,研究了Ti-B-Cu体系中TiB2增强相的生成机制;通过测试硬度、拉伸强度、导电率等研究了TiB2/Cu复合材料的力学性能和电学性能。综合液淬分析和差热结果可知:在Ti-B-Cu体系中,先后生成Cu3Ti和TiB2。其中TiB2主要是靠生成中间相Cu3Ti时产生的富B相和Cu3Ti分解产生的富Ti相之间的相互扩散产生原位反应生成的。通过控制反应原料的组成,可以得到纯粹的TiB2反应产物;在Ti-B-Cu体系中,针对不同的铜含量,TiB2增强相大量生成时的温度均为1048℃左右。实验结果表明:在电磁场条件下,反应体系同时受到电磁场和热场的综合作用,反应区内热量的积累速率更大,反应更容易进行。利用电磁场条件下的原位合成反应在铜基体内生成了电学和力学性能优良,颗粒细小,且分布弥散的TiB2颗粒增强相,TiB2尺寸约为50-300纳米左右。通过该工艺制备的原位自生TiB2/Cu复合材料具有良好的力学性能和电学性能,成分为3.5wt.%的TiB2/Cu复合材料,维氏硬度达127.6HV,导电率达74.5%IACS,而对应的抗拉强度高达574.8MPa。更多还原

【Abstract】 The copper matrix composite reinforced by in-situ nano-TiB2 was prepared by electromagnetism sintering and hot pressing of boron (B), titanium (Ti) and copper (Cu) powders, which were evenly mixed and then cold molding by press machine. The microstructures and phase composition of TiBB2/Cu compositeswere studied with SEM, XRD. The formation mechanism of TiB2B in Ti-B-Cusystem also was studied by quenching and differential scanning calorimetry .The mechanical properties and conductive properties of composites were tested with hardness-testing device, strength test and conductivity measuration. Thermodynamics calculation and differential scanning calorimetry indicate that Cu3Ti and TiB2 are successively produced in the Ti-B-Cu system.The formation of TiBB2 depends mainly on the diffusion and chemical reaction of the B rich phase arising from the formation of Cu3Ti and the Ti rich phase due to melting of Cu3Ti.Through controlling composition of the composites, we can get pure reaction product TiB2B. In Ti-B-Cu system, the temperature of synthesis of TiB2 is about 1048℃whatever the content of copper. Experimental results show that the synthesis system is affected by the electromagnetic and thermal fields. Then the rate of heat accumulation in reaction zone was faster and the reaction was easier. TiBB2 reinforcement particleswith fine grain, dispersed distribution and good conductibility are fabricated by combustion synthesis within copper matrix. The sizes of the reinforcement particles are nearly 50-300nm. The TiBB2/Cu composite fabricated by this technics has excellent mechanical properties and conductibility. The hardness, conductivity and strength of 3.5wt.%TiB2 reinforced copper matrix composite are 127.6HV, 74.5%IACS and 574.8MPa.更多还原