激光熔覆-等離子噴涂熱障涂層高溫氧化結(jié)構(gòu)及殘余應(yīng)力
發(fā)布時間:2018-05-11 00:11
本文選題:熱障涂層 + 激光熔覆; 參考:《材料熱處理學報》2017年01期
【摘要】:采用半導體激光熔覆與等離子噴涂相結(jié)合的方法制備了YSZ/CoCrAlY熱障涂層,利用掃描電鏡(SEM)、X-射線衍射儀(XRD)分析了其高溫氧化后的結(jié)構(gòu)特征,建立了其高溫氧化后應(yīng)力特征的計算模型,并與拉曼顯微光譜儀測試的應(yīng)力進行了對比。結(jié)果表明:高溫氧化后,粘結(jié)層組織為垂直于基體表面的樹枝晶結(jié)構(gòu),陶瓷層出現(xiàn)細小裂紋與部分脫落現(xiàn)象,ZrO_2發(fā)生單斜相向立方相或正方相轉(zhuǎn)變時伴隨有4%的體積收縮,陶瓷層產(chǎn)生拉應(yīng)力;ZrO_2發(fā)生立方相或正方相向單斜相轉(zhuǎn)變時伴隨有6%的體積膨脹,陶瓷層產(chǎn)生壓應(yīng)力;熱障涂層經(jīng)過750℃高溫氧化108 h后,通過模型計算陶瓷層殘余應(yīng)力為496.5 MPa的壓應(yīng)力,與拉曼光譜測量結(jié)果(434.8 MPa)吻合得較好。
[Abstract]:YSZ/CoCrAlY thermal barrier coatings were prepared by laser cladding and plasma spraying. The structural characteristics of the coatings after high temperature oxidation were analyzed by scanning electron microscopy (SEM), and the stress characteristics of the coatings were calculated. The stress measured by Raman microspectrometer is compared with that measured by Raman microspectrometer. The results show that the microstructure of the bonding layer is dendritic structure perpendicular to the surface of the substrate after oxidation at high temperature, and the fine cracks and partial shedding of ceramic layer occur during the monoclinic phase to cubic phase or square phase transition with 4% volume contraction. During the transition from cubic phase or square phase to monoclinic phase, there is 6% volume expansion and compressive stress in ceramic layer, and the thermal barrier coating is oxidized at 750 鈩,
本文編號:1871534
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