【作者】 高丽娜；

【导师】 陈文革；

【作者基本信息】 西安理工大学 ， 材料科学与工程， 2009， 硕士

【摘要】 随着经济发展以及医疗体制改革的加快,医用CT机已经成为一般医院的常规检测设备之一,对其中主要的部件阳极靶材提出了轻质、高导热、高热容、良好的高温热震性等要求。鉴于钨/钼/石墨复合材料具有良好的高温性能,本研究旨在通过选择适当的工艺路线以及工艺参数制备出满足性能要求同时能够实现工业化生产的阳极靶材。本研究首先用粉末冶金技术制备出性能较好的W/Mo双金属层,然后通过扩散焊接将其与三高石墨连接在一起,从而制备出最终的W/Mo/石墨复合阳极靶材。通过扫描电镜、激光导热仪、涡流电导仪等手段研究整体靶材的性能,探讨各工艺参数对复合靶材性能和组织结构的影响,获得的主要成果有：1采用铺层设计冷压成型后,在1700℃,保温4h,真空度为1.8×10-2Pa下可制备出组织分布均匀,相对密度为90.61%的钨钼双金属层。其导热系数为121.7 W·m-1·K-1,界面剪切强度为115MPa。2采用Ni,Mn,Ag,Cu作为添加剂,在1300℃-1350℃,真空度3.8x10-3Pa,5-10MPa的压力下,扩散焊接20-30min制备的Mo/石墨复合层,界面剪切强度为8.33MPa,低于石墨本身的剪切强度；采用Ni, Ti, Zr作为添加剂,在1300℃-1350℃,真空度3.8x10-3Pa,5-10MPa的压力下,扩散焊接20-30min制备的Mo/石墨复合层,界面剪切强度为10.33MPa,高于石墨本身的剪切强度。3 W/Mo双金属层的断裂为解理脆性断裂,且具有一定的抗热震能力；Mo/石墨复合层的断裂为准解理脆性断裂,且发现在结合面处有添加组元或成份的扩散与偏聚现象。4本研究制备的W/Mo/石墨复合靶材能满足一定的性能要求,但与国外同类靶材尚有一定的差距。本研究为高性能X射线管用钨/钼/石墨复合靶材的产业化和工业化提供了一定的实验基础和理论依据。更多还原

【Abstract】 With the development of economy and the reform of the Medicare system medical CT has became a normal detection device in ordinary hospitals. Required the anode target have light weight, high thermal conduction and high performance in thermal shock, etc. The tungsten/molybdenum/graphite composite target has good high temperature behavior. This research aims at preparing the anode target can meet the demand and also can be produced by commercial process with suitable processing.The major processing is to connect the tungsten/molybdenum bimetal prepared by powder metallurgy with the graphite through diffusion welding. Then research the target’s performance with SEM (scanning electron microscope), Flash Thermal Diffusion Instrument, eddy-current conductivity apparatus, etc. Then discuss each processing parameter’s contribution to the capability and histology of the target. The following are the main results obtained:1 The tungsten/molybdenum bimetal sintered at 1700℃, holding for 4 h under vacuum condition (1.8×10-2Pa) has fine and dense microstructure,90.61% relative density, a gentle transition layer between tungsten and molybdenum. The thermal conductivity was 121.7 W·m-1·K-1 and the bonding strength was 115MPa (shear).2 Utilizing the mixture of Ni, Mn, Ag and Cu as adhesive, the molybdenum/graphite composite layer prepared at 1300℃-1350℃, with press of 5-10MPa holding for 20-30min under vacuum condition (3.8×10-3Pa) has low bonding shear strength (8.33MPa) lower than the nature shear strength of graphite. Utilizing the mixture of Zr, Ni and Ti as adhesive, the molybdenum/graphite composite layer prepared at 1300℃-1350℃, with press of 5-10MPa holding for 20-30min under vacuum condition (3.8×10-3Pa) has large bonding shear strength (10.33 MPa) higher than the nature shear strength of graphite. 3 The fracture of the tungsten/molybdenum bimetal layer was cleavage brittle fracture. The tungsten/molybdenum bimetal layer has some ability of resisting thermal shock. The fracture of the molybdenum/graphite layer was quasi-cleavage brittle fracture. Adhesive has get diffusion and segregation in the bonding interface.4 Though the tungsten/molybdenum/graphite composite target prepared by this research can meet parts of capabilities required, it has some distance from the like products abroad. This research has provides many experimental foundations and bases for the industrialization and widely use of the tungsten/molybdenum/graphite composite target for X-ray tube.更多还原