【作者】 董雁国；

【导师】 李工；

【作者基本信息】 燕山大学 ， 材料学， 2010， 硕士

【摘要】 锆以其较好的抗核辐射性、耐腐蚀性和较低的热膨胀系数等突出特点,成为一种重要的新型结构材料。本文从金属锆的结构出发,以改善金属锆的性能为目的,使用六面顶压机,设定保温时间,同时调整压力、温度两个参数,对金属锆进行处理,并对处理前后的结构变化及性能进行了研究。利用X射线衍射仪测试、分析了高温高压后金属锆的结构变化。结果显示,金属锆在理论相变开始温度之前的高温高压处理,发生了结构转变。平均晶粒尺寸的计算结果表明了温度和压力对晶粒尺寸都有一定的影响。利用高精度热膨胀仪研究了处理前后金属锆在连续加热条件下的热膨胀行为。结果表明高温高压处理后,金属锆的热膨胀系数下降。利用电化学实验站进行了耐蚀性能测定,极化曲线显示,处理后的金属锆的耐蚀性能有所改善,在800℃各压力条件下,耐蚀性能显著提高。利用端面摩擦磨损试验机对处理前后金属锆进行了摩擦磨损试验,并用扫描电子显微镜对试样的表面形貌进行分析。结果表明,摩擦磨损过程中,主要为粘着磨损,处理后的金属试样的失重量较小,耐磨性能提高。硬度测试结果显示,随着压力、温度的升高,自然时效时间的延长,硬度显著增加。更多还原

【Abstract】 Metal zirconium becomes a very important novel structure material for its advantages such as anti-nuclear radioactive, corrosion resistance and low thermal expansion coefficient and so on.The purpose of this work was to improve the properties of metal zirconium from the perspective of the structure of metallic zirconium. The cubic anvil high pressure apparatus was used to produce high pressure. The metal zirconium was treated by changing the pressure and temperature simultaneously, when the holding time was set. The microstructures and properties of the metal zirconium were studied.The phases and microstructure of the metal zirconium before and after treated under high temperature and high pressure were analyzed by X-ray diffraction. It was shown that there was significant change in phases of the metal zirconium treated under before the theoretical phase transition temperature. The calculation results of the average grain size showed that the size of the particle was changed under the combined effect of the temperature and pressure.The thermal expansion behavior of the metal zirconium before and after treated under high temperature and high pressure was investigated under the conditions of continuous heating by the thermal expansion equipment. The result shows that the thermal expansion coefficient of the metal zirconium treated descreases. The corrosion properties of the metal zirconium were analyzed by CHI660A electrochemical workstation. The corrosion resistance significantly increased in a particular temperature and pressure.The friction and wear experiment of the metal zirconium before and after treated under high temperature and high pressure was handled by friction and wear testing machine. The surface morphology of the sample was analyzed by the scanning electron microscope. The result shows that friction and wear process is mainly adhesive wear. The weight loss of metal samples treated was less, the wear resistance was improved. The result of hardness test shows the higher the pressure and temperature and the longer the natural aging time, the greater microhardness.更多还原