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钛合金结构在复杂载荷和工况下的损伤容限对现代飞行器安全十分重要,但至今没有结构三维几何尺寸因素对材料高温断裂性能的影响结果报道.利用新发展的光测断裂试验技术,对航空结构材料TC11高温钛合金制成的紧凑拉伸剪切试样,在3种不同温度条件下进行了多种厚度(1.8～7.1mm)的I/II复合型断裂试验,系统分析了温度、厚度和复合载荷对断裂承载力和裂纹起裂角的影响.结果表明,TC11材料在室温下断裂承载力随厚度增加单调降低;在高温下则呈现与室温下不同的厚度效应:温度明显降低2mm试样的承载能力,而增强7mm试样的承载能力,4mm试样的承载能力则较少变化.I/II复合加载时起裂角在室温和高温条件下都存在一定的厚度效应和温度效应.这些复杂的厚度-温度耦合效应不能用已有断裂理论准确预测,必须发展新的三维复合型断裂理论和评定技术.
The damage tolerance of titanium alloy structure under complex load and working conditions is very important for the safety of modern aircraft, but so far there is no report on the influence of the three-dimensional geometric dimension of the structure on the high-temperature rupture performance of the material.Based on the newly developed photometric fracture testing technology, Aerospace structural materials TC11 high temperature titanium alloy compact tensile shear specimens, at three different temperature conditions for a variety of thickness (1.8 ~ 7.1mm) I / II composite fracture test, the system analysis of temperature, Thickness and composite load on the fracture capacity and crack initiation angle.The results show that the fracture bearing capacity of TC11 monotonically decreases with the increase of the thickness at room temperature and different from the room temperature at high temperature: the temperature decreases obviously by 2mm But the carrying capacity of 7mm specimen is enhanced and the bearing capacity of 4mm specimen is less changed.The crack initiation angle at I / II composite loading has certain thickness effect and temperature effect at room temperature and high temperature These complex thickness - temperature coupling effects can not be accurately predicted using the existing fracture theory, and new three - dimensional composite fracture theory and assessment techniques must be developed.