Study On Vacuum Properties Of CuCrZr Based On Synchrotron Radiation High Heat Load

CuCrZr is a kind of precipitation hardened high strength and high conductivity copper alloy material.Domestic CuCrZr raw materials are of good quality,various shapes and sizes,and low procurement cost.Therefore,CuCrZr has a good prospect in the application of the high heat load components of synchrotron rdiation source.Under this engineering projects background,the vacuum performance of CuCrZr applied in synchrotron radiation source was studied from the aspects of thermal outgassing rate,photoelectric desorption,mechanical strength and welding.The research results were applied to the development of CuCrZr high heat load components of Shanghai Synchrotron Radiation Faciilty.Switching between two pumping paths method and XPS surface analysis technique were used to study the thermal performance of CuCrZr.Through the analysis of experimental data,it was concluded that the composition and state of oxide on the surface of CuCrZr were the important factors affecting the thermal outgassing rate.The vacuum pretreatment process was put forward to effectly reduce the thermal outgassing rate of CuCrZr.After being pretreated by vacuum furnace at400℃,dense chromium trioxide with good thermal stability was formed on the surface of CuCrZr.The thermal outgassing rate of CuCrZr after baking at 150℃was1.64×10^-11Pa·L·s^-1·cm^-2.The photoelectric desorption performance of CuCrZr was studied in synchrotron radiation light source for the first time.The relationship between photon stimulated desorption yield with integrated photon dose and incident angles of CuCrZr was analyzed.At the initial stage of experiment,CO₂was the most sensitive to synchrotron radiation and the increase of ion current was the largest.The photon stimulated desorption yield was 1.27×10^-6for a integrated photon dose of 1.27×10²⁵photons·mm^-2.The photon stimulated desorption yield increased with the decrease of the photon incidence angle.The photon stimulated desorption yield at 5°angle was about two times of that at normal incidence.Based on the data of tensile and fatigue tests,the design criteria of CuCrZr materials and welded joints in the development of high heat load components was proposed for the first time.The overall temperature threshold of CuCrZr body material was less than 550℃.The maximum equivalent stress at a certain temperature T was less than（353.6-0.0477 T-0.0006 T²）（MPa）.The strength and plasticity of CuCrZr welded joints were far less than that of raw materials,so they cannot be used as surfaces with high intensity requirements for photon incidence.In the process of welding,attention should be paid to the control of temperature in the area around the weld so as not to affect the strength of the CuCrZr body material.CuCrZr after high temperature was not suitable for use as the absorber materials in high heat load components.The above experimental results provided a strong basis for the design of the CuCrZr heat load components in Shanghai Synchrotron Radiation Faciilty,such as absorber 2 of storage ring C13 unit and the white beam slit of BL02U2 beamline.