高温环境下热障涂层力学性能压痕原位表征分析
发布时间：2018-11-05 10:17
【摘要】：热障涂层(Thermal barrier coatings,简称TBCs)以其卓越的隔热、耐高温、耐磨损、耐冲蚀等性能,被广泛应用于航空涡轮发动机关键隔热防护材料,在航空航天、国防科技领域以及国民经济中发挥了巨大作用。然而,在真实服役环境中,由于受到材料参数不匹配、界面缺陷、工作温度变化、残余应力和外加载荷等因素影响,涂层体系通常发生难以预知的表/界面剥落失效。本文采用高温维氏压痕原位测试系统,实现了对脆性涂层材料体系硬度、断裂韧性和残余应力等力学性能高温实时原位测试表征,获得了涂层体系表/界面硬度、断裂韧性和残余应力随温度演变关系。主要研究内容如下:第一,通过对现有的常温小负荷维氏压痕仪进行升级改进,集成包含加载系统、高温加热及控制系统、原位观测系统、图像采集系统、真空和冷却循环系统以及其他辅助装置,研制出高温维氏压痕原位测试系统,实现1100℃范围内热障涂层材料体系硬度、断裂韧性及残余应力等力学性能的实时原位表征分析。第二,采用自主研制的高温压痕原位测试系统,原位表征了8wt.%Y2O3部分稳定的ZrO2(8YSZ)热障涂层表面硬度、断裂韧性和残余应力随温度演变关系。结果表明:当测试温度由室温变化到1100℃时,涂层表面硬度由2.96 GPa降低为1.06 GPa。考虑涂层内部残余应力对表面断裂强度因子的贡献,随着测试温度由室温变化到1100℃,求得涂层表面断裂韧性先由0.71 MPa·m1/2减小为0.54MPa·m1/2,然后增大到1.03 MPa·m1/2;对应的残余应力初始阶段表现为残余压应力,由-66.4 MPa变为-15.38 MPa,在900~1000℃温度区间,残余压应力转变为残余拉应力,1100℃时残余拉应力达到12.92 MPa。第三,采用自主研制的高温压痕原位测试系统,原位表征了热障涂层横截面和粘结层硬度、界面处断裂韧性和残余应力随温度的演变规律。结果表明,当测试温度由室温变化到1100℃时,涂层横截面硬度由3.28 GPa降低为1.23 GPa;粘结层硬度由3.06 GPa降低为2.13 GPa。考虑涂层与粘结层界面处残余应力的影响,界面断裂韧性数值由0.25 MPa·m1/2增大到0.48 MPa·m1/2,然后减小到0.1MPa·m1/2;对应残余应力从-33.04 MPa增大为-50.96 MPa,然后残余压应力继续减小,在1100℃附近转变为拉应力,大小为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，
本文编号：2311755
[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，
本文编号：2311755
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