TiAlNb alloy is one of the candidate high strength titanium alloy materials under consideration for compressor disc, which will endure dwell loading at high peak stress level during service. In this work, low cycle fatigue (LCF) and low cycle dwell fatigue (LCDF) deformation behaviors and damage mechanism of TiAlNb alloy with lamellar microstructure under high loading level were investigated. The results show that fatigue life is highly dependent on the peak stress () and dwell time (). With increasing the , the LCF life decreases gradually since higher loading stress can accelerate plastic strain accumulation and lead to faster crack propagation. When at the same , the LCDF life is lower than the LCF life due to greater plastic strain accumulation caused by dwell effect, indicating a dwell life debit of the TiAlNb alloy. Moreover, dwell fatigue sensitivity exhibits an increasing trend as the increases. Under different loading waveforms, the fractography shows remarkably different features. Crack source of LCF appears on sample surface, while crack source of LCDF appears on surface and sub-surface of sample. The research of LCDF behavior is relevant to aviation industry to prevent premature failure of rotating components made of TiAlNb alloys.

中文翻译：

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峰值应力和保压时间对片状Ti-22Al-23Nb-2(Mo,Zr)合金疲劳损伤行为的影响


TiAlNb 合金是压缩机盘考虑的候选高强度钛合金材料之一，它将在使用过程中承受高峰值应力水平的驻留载荷。本文研究了片状组织TiAlNb合金在高载荷水平下的低周疲劳（LCF）和低周驻留疲劳（LCDF）变形行为和损伤机制。结果表明，疲劳寿命高度依赖于峰值应力 () 和停留时间 ()。随着 的增加，LCF 寿命逐渐缩短，因为较高的负载应力会加速塑性应变积累并导致更快的裂纹扩展。同时，由于驻留效应导致更大的塑性应变积累，LCDF 寿命低于 LCF 寿命，表明 TiAlNb 合金的驻留寿命较差。而且，驻留疲劳敏感性随着温度的增加呈现出增加的趋势。在不同的加载波形下，断口显示出明显不同的特征。 LCF的裂纹源出现在样品表面，LCDF的裂纹源出现在样品的表面和亚表面。 LCDF行为的研究与航空工业相关，以防止TiAlNb合金制成的旋转部件过早失效。