Failure Behavior of Plasma-Sprayed Yttria-Stabilized Zirconia Thermal Barrier Coatings Under Three-Point Bending Test via Acoustic Emission Technique

Influence of SiC Addition on Mechanical Behavior of Thermal Barriers with the Aid of Acoustic Emission

“…In order to generate cracks in the coatings, the three-point flexural test, one of the methods most collected in the literature for this purpose, was performed [12,14,15], with a configuration like the one presented in Figure 1a,b.…”

“…In order to generate cracks in the coatings, the three-point flexural test, one of the methods most collected in the literature for this purpose, was performed [12,14,15], with a configuration like the one presented in Figure 1a To know the stress state of the ceramic coating at a given moment, Equation ( 1) is used [16], which allows the calculation of the maximum stress on the thermal barrier as a function of the load applied during the three-point flexural test.…”

“…The use of infrared thermography and acoustic emission techniques to monitor crack evolution is quite common in literature [11][12][13][14][15].…”

Research Progress of Failure Mechanism of Thermal Barrier Coatings at High Temperature via Finite Element Method

“…A host of research results have showed that the cracks exist in the top-coat layer or near the TC (top-coat)/TGO interfaces in APS-TBCs. During the thermal shock, these cracks can propagate along the stratiform interface or through lamella under complex stress states [44][45][46]. The spallation of coating frequently take place owing to the crack initiation along the layer interface, which is accountable for the failure of APS-TBCs.…”

Bending Failure Mechanism Study of Si-Cr-Ti High Temperature Oxidation Resistance Coating via Acoustic Emission Technique

“…铌合金具有优异的高温力学性能而用作航空航 天领域的结构材料 [1][2][3] ，但是较差的高温抗氧化性能 又制约了铌合金的应用 [4][5][6] 。因此，通常采用涂层包 覆的方法来提高合金的高温抗氧化性能 [7][8][9] 。常见的 高温防护涂层，如 Si-Cr-Ti 体系涂层已经成功应用 多年 [2,[10][11] 。研究表明，涂层在高温服役过程中结 构与组分的演变是涂层失效的主要原因，其中微裂 纹的影响最为显著 [12] 。随着航天技术的进一步发展， 对高温抗氧化涂层提出了更高的使用要求。为了针 对性地提高涂层性能，对其破坏过程中裂纹演化过 程的研究十分重要。 对于高温抗氧化涂层失效过程的研究，通常采 用分时采样的方法，即对不同服役时间的样品进行 机械加工，利用扫描电子显微镜观察氧化前后涂层 的形貌与组分的变化情况 [12][13][14][15][16] 。但这种方法在制样 过程中会对涂层造成二次伤害， 干扰分析失效机理。 声发射技术(AE) [17][18][19][20][21] 、数字图像相关法(DIC) [22][23][24][25] 、光致发光光谱法(PLPS) [26][27][28][29][30] 、红外光谱法 [31][32] 和热成像法 [33] 等无损检测技术常被用来确定 损伤部位以及评价损伤程度。高温抗氧化涂层在高 温服役条件下的失效过程是一个与温度场变化、材 料成分变化以及微结构演变等联系在一起的动态变 化过程，静态研究方式势必会掩盖涂层裂纹结构的 真实信息。因此，在这些方法中，声发射技术兼具 实时、无损和连续监测的优点，十分适合进行破坏 过程机理的研究。目前对于声发射技术在失效过程 研究的应用主要集中于岩土材料、复合材料以及热 障涂层 [17][18][19][20][21] ，而对于 Si-Cr-Ti 高温抗氧化涂层失效 机理的研究未见报道。尽管同为涂层，由于声发射 信号对材料成分以及结构的敏感性，仍然有必要进 行 Si-Cr-Ti 高温抗氧化涂层失效机理中声发射信号 的研究。 由于声发射信号的特点与裂纹的破坏模式紧密 相关，而与引起裂纹的外载荷属性无关 [20] [40] ：…”