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  本文選題：非線性超聲 + 汽輪機耐熱材料　； 參考：《華東理工大學》2015年碩士論文

【摘要】：超超臨界汽輪機高溫部件長期服役會產(chǎn)生蠕變損傷,對設備的安全運行存在潛在的威脅,快速、有效地檢出高溫構件蠕變損傷狀況對保證設備服役安全意義重大。最近研究表明,材料損傷程度與超聲波非線性效應有緊密的聯(lián)受,受到學者們的廣泛關注。本文利用實驗室模擬獲得汽輪機螺栓、轉子試樣的不同蠕變損傷水平,進行了非線性超聲縱波表征耐熱材料蠕變損傷狀態(tài)的實驗研究,主要研究內容和結果如下：(1)汽輪機鎳基高溫螺栓材料In783蠕變損傷狀態(tài)的非線性超聲縱波表征實驗研究。以包含不同蠕變損傷水平的高溫鎳基螺栓材料In783為對象,進行蠕變損傷水平的非線性超聲縱波表征實驗,完成了不同損傷試樣的微觀組織和機理分析。結果發(fā)現(xiàn)：超聲縱波非線性參量隨蠕變變形的增大而單調增加,顯微硬度隨蠕變應變的變化與超聲非線性變化趨勢一致,表明超聲縱波非線性參量與材料力學性能退化存在函數(shù)關聯(lián)。超聲非線性參量的增大主要源于材料內部位錯密度的增加及析出相長大。基于位錯-析出相模型預測得到了與實驗測量值較一致的結果,表明位錯-析出相模型可較好描述鎳基高溫合金與超聲非線性參量的關系。(2)汽輪機轉子鐵素體耐熱鋼FB2蠕變損傷狀態(tài)的非線性超聲縱波表征實驗研究。進行了包含不同蠕變損傷水平的鐵素體鋼FB2的非線性超聲縱波表征實驗,完成了不同損傷試樣的微觀組織和機理分析。結果發(fā)現(xiàn)：超聲縱波非線性參量隨汽輪機轉子鋼蠕變變形的增大而單調增加,且超聲非線性參量變化與蠕變損傷機制存在函數(shù)關系。進一步,以位錯密度為中間量,建立了穩(wěn)態(tài)蠕變變形速率與超聲非線性參量的函數(shù)關系。
[Abstract]:The long-term service of the ultra-supercritical steam turbine high temperature components will cause creep damage, which has a potential threat to the safe operation of the equipment. It is of great significance to detect the creep damage condition of the high temperature components quickly and effectively to ensure the safety of the equipment service. Recent studies have shown that the damage degree of materials is closely related to the nonlinear effect of ultrasonic wave, which has attracted extensive attention of scholars. In this paper, different creep damage levels of turbine bolts and rotor specimens are obtained by laboratory simulation, and the experimental study of nonlinear ultrasonic longitudinal wave characterizing creep damage state of heat-resistant materials is carried out. The main contents and results are as follows: (1) the experimental study of nonlinear ultrasonic longitudinal wave characterization of In783 creep damage of nickel based high temperature bolt material for steam turbine. The nonlinear ultrasonic longitudinal wave characterizing the creep damage level of high temperature nickel-base bolt material In783 with different creep damage levels was carried out. The microstructure and mechanism of different damage samples were analyzed. The results show that the nonlinear parameters of ultrasonic longitudinal wave increase monotonously with the increase of creep deformation, and the variation of microhardness with creep strain is consistent with that of ultrasonic nonlinearity. It is shown that there is a functional correlation between the nonlinear parameters of ultrasonic longitudinal wave and the degradation of mechanical properties of materials. The increase of ultrasonic nonlinear parameters is mainly due to the increase of dislocation density and the growth of precipitated phase. Based on the dislocation-precipitation model, the predicted results are in good agreement with the experimental results. It is shown that the dislocation precipitation phase model can better describe the relationship between nickel base superalloy and ultrasonic nonlinear parameters. The experimental study of nonlinear ultrasonic longitudinal wave characterization of FB2 creep damage state of ferrite heat-resistant steel in steam turbine rotor is presented. The nonlinear ultrasonic longitudinal wave characterization experiments of ferrite steel FB2 with different creep damage levels were carried out. The microstructure and mechanism of different damage samples were analyzed. The results show that the ultrasonic longitudinal wave nonlinear parameters increase monotonously with the increase of creep deformation of turbine rotor steel, and there is a functional relationship between the variation of ultrasonic nonlinear parameters and the creep damage mechanism. Furthermore, the functional relationship between steady state creep deformation rate and ultrasonic nonlinear parameters is established with dislocation density as the intermediate value.
【學位授予單位】：華東理工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TB34

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本文編號：1885416