發(fā)布時(shí)間：2018-11-05 10:17

【摘要】：熱障涂層(Thermal barrier coatings,簡(jiǎn)稱TBCs)以其卓越的隔熱、耐高溫、耐磨損、耐沖蝕等性能,被廣泛應(yīng)用于航空渦輪發(fā)動(dòng)機(jī)關(guān)鍵隔熱防護(hù)材料,在航空航天、國(guó)防科技領(lǐng)域以及國(guó)民經(jīng)濟(jì)中發(fā)揮了巨大作用。然而,在真實(shí)服役環(huán)境中,由于受到材料參數(shù)不匹配、界面缺陷、工作溫度變化、殘余應(yīng)力和外加載荷等因素影響,涂層體系通常發(fā)生難以預(yù)知的表/界面剝落失效。本文采用高溫維氏壓痕原位測(cè)試系統(tǒng),實(shí)現(xiàn)了對(duì)脆性涂層材料體系硬度、斷裂韌性和殘余應(yīng)力等力學(xué)性能高溫實(shí)時(shí)原位測(cè)試表征,獲得了涂層體系表/界面硬度、斷裂韌性和殘余應(yīng)力隨溫度演變關(guān)系。主要研究?jī)?nèi)容如下:第一,通過對(duì)現(xiàn)有的常溫小負(fù)荷維氏壓痕儀進(jìn)行升級(jí)改進(jìn),集成包含加載系統(tǒng)、高溫加熱及控制系統(tǒng)、原位觀測(cè)系統(tǒng)、圖像采集系統(tǒng)、真空和冷卻循環(huán)系統(tǒng)以及其他輔助裝置,研制出高溫維氏壓痕原位測(cè)試系統(tǒng),實(shí)現(xiàn)1100℃范圍內(nèi)熱障涂層材料體系硬度、斷裂韌性及殘余應(yīng)力等力學(xué)性能的實(shí)時(shí)原位表征分析。第二,采用自主研制的高溫壓痕原位測(cè)試系統(tǒng),原位表征了8wt.%Y2O3部分穩(wěn)定的ZrO2(8YSZ)熱障涂層表面硬度、斷裂韌性和殘余應(yīng)力隨溫度演變關(guān)系。結(jié)果表明:當(dāng)測(cè)試溫度由室溫變化到1100℃時(shí),涂層表面硬度由2.96 GPa降低為1.06 GPa�？紤]涂層內(nèi)部殘余應(yīng)力對(duì)表面斷裂強(qiáng)度因子的貢獻(xiàn),隨著測(cè)試溫度由室溫變化到1100℃,求得涂層表面斷裂韌性先由0.71 MPa·m1/2減小為0.54MPa·m1/2,然后增大到1.03 MPa·m1/2;對(duì)應(yīng)的殘余應(yīng)力初始階段表現(xiàn)為殘余壓應(yīng)力,由-66.4 MPa變?yōu)?15.38 MPa,在900~1000℃溫度區(qū)間,殘余壓應(yīng)力轉(zhuǎn)變?yōu)闅堄嗬瓚?yīng)力,1100℃時(shí)殘余拉應(yīng)力達(dá)到12.92 MPa。第三,采用自主研制的高溫壓痕原位測(cè)試系統(tǒng),原位表征了熱障涂層橫截面和粘結(jié)層硬度、界面處斷裂韌性和殘余應(yīng)力隨溫度的演變規(guī)律。結(jié)果表明,當(dāng)測(cè)試溫度由室溫變化到1100℃時(shí),涂層橫截面硬度由3.28 GPa降低為1.23 GPa;粘結(jié)層硬度由3.06 GPa降低為2.13 GPa�？紤]涂層與粘結(jié)層界面處殘余應(yīng)力的影響,界面斷裂韌性數(shù)值由0.25 MPa·m1/2增大到0.48 MPa·m1/2,然后減小到0.1MPa·m1/2;對(duì)應(yīng)殘余應(yīng)力從-33.04 MPa增大為-50.96 MPa,然后殘余壓應(yīng)力繼續(xù)減小,在1100℃附近轉(zhuǎn)變?yōu)槔瓚?yīng)力,大小為7.63 MPa。
[Abstract]:Thermal barrier coating (Thermal barrier coatings,) is widely used in aviation turbine engine for its excellent thermal insulation, high temperature resistance, wear resistance, erosion resistance and so on. National defense science and technology as well as the national economy has played a great role. However, in the real service environment, due to the influence of material parameters mismatch, interface defects, working temperature change, residual stress and applied load, the surface / interface spalling failure of coating system is usually unpredictable. In this paper, the mechanical properties of brittle coating system, such as hardness, fracture toughness and residual stress, were measured in situ by using high temperature Vickers indentation in-situ testing system. The surface / interface hardness of the coating system was obtained. Fracture toughness and residual stress change with temperature. The main research contents are as follows: first, by upgrading and improving the existing Vickers indentation instrument at room temperature and small load, the integration includes loading system, high temperature heating and control system, in situ observation system, image acquisition system, etc. A high temperature Vickers indentation in-situ testing system has been developed in vacuum, cooling circulatory system and other auxiliary devices. The mechanical properties of thermal barrier coating system such as hardness, fracture toughness and residual stress can be analyzed in situ at 1100 鈩，

本文編號(hào)：2311755