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Research on Tungsten-molybdenum-graphite Composite Anode Target for X-ray Tube in Medical Computerized Tomography

Author: GaoLiNa
Tutor: ChenWenGe
School: Xi'an University of Technology
Course: Materials Science and Engineering
Keywords: Target Powder Metallurgy Diffusion welding Refractory metal
CLC: R197.39
Type: Master's thesis
Year: 2009
Downloads: 61
Quote: 0
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Abstract


With the acceleration of economic development as well as health care reform , medical CT machine has become one of the General Hospital of conventional testing equipment , one of the main components anode target lightweight , high thermal conductivity , high heat capacity , excellent high-temperature thermal shock and other requirements . Given the tungsten / molybdenum / graphite composites have good high temperature performance , The purpose of this study is to be prepared by selecting the appropriate process route and process parameters to meet the performance requirements at the same time be able to achieve the industrial production of the anode target . This study was prepared by powder metallurgy technology out the better performance of the W / Mo double metal layer, and then by diffusion welding with three high graphite are connected together , thereby preparing a final W / an Mo / graphite composite anode target . The main achievements of the overall performance of the target by means of scanning electron microscopy , laser , thermal conductivity tester , eddy current conductance instrument to explore the impact of various process parameters on the performance and the organizational structure of the composite target gained : 1 ply design cold molding 1700 ℃, insulation 4h, a vacuum degree of 1.8 × 10-2Pa uniform tissue distribution can be prepared , the relative density of the double metal layer of 90.61% of tungsten and molybdenum . Its thermal conductivity 121.7 W · m-1 · K-1, the interfacial shear strength of 115MPa . 2 Ni, Mn, Ag, Cu as an additive, in 1300 ℃ -1350 ℃, under the pressure of the degree of vacuum of 3.8x10-3Pa ,5-10MPa , diffusion welding 20-30min Preparation of a Mo / graphite composite layer , the interfacial shear strength 8.33MPa, less than the shear strength of the graphite itself ; Ni, Ti, Zr as an additive , in 1300 ℃ -1350 ℃, the degree of vacuum to a pressure of 3.8x10-3Pa ,5-10MPa , diffusion welding 20-30min prepared Mo / graphite composite layer interfacial shear strength 10.33MPa, and higher than the shear strength of the graphite itself . 3 W / Mo bimetallic layer fracture cleavage brittle fracture and thermal shock ; fracture of the Mo / graphite composite layer quasi-cleavage brittle fracture , and add elements or ingredients found at the joint surface diffusion and segregation phenomenon. Four studies prepared by W / Mo / graphite composite target to meet certain performance requirements , but there is a gap with similar foreign targets . In this study, for the high-performance X-ray tube tungsten / molybdenum / graphite composite target industrialization and industrialization experimental and theoretical basis .

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CLC: > Medicine, health > Preventive Medicine,Health > Health care organizations and career ( Health Management ) > Health care systems and institutions > Hospitals, general hospitals > Medical Devices \u0026 Equipment
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