In this work, the fatigue properties of in-situ TiB particle-reinforced 7050 Al-matrix (TiB/7050Al) composites at room temperature (RM), 100 ℃ and 150 ℃ were studied, respectively, and the microstructure changes, fatigue fracture characteristics and fracture mechanism were analyzed. The results indicate that when the fatigue temperature increased, the amount of S phase precipitation along grain boundaries increases, forming a banded distribution with TiB particles near the grain boundary regions. The RM fatigue limit of the composite is high up to 307.5 MPa. Under the same fatigue strength, TiB/7050 composites can withstand fatigue cycles far greater than 7050Al alloy. With the increase of temperature, the fatigue performance of the composite gradually decreased, and unlike at RM and 100 ℃, the use of Weibull three-parameter model is necessary to obtain a satisfactory - curve at 150 ℃. In some locations of the steady-state crack propagation stage, the direction and spacing of fatigue striations were influenced by grain orientation, grain boundaries and TiB particle bands. Therefore, the effects of TiB particles, grain boundaries, and precipitations on the fatigue processes were analyzed to reveal the strengthening mechanisms of the composite.

中文翻译：

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原位TiB2/7050Al复合材料不同温度下的高疲劳性能及微观机制

本工作分别研究了原位TiB颗粒增强7050铝基（TiB/7050Al）复合材料在室温（RM）、100℃和150℃下的疲劳性能，以及显微组织变化、疲劳断裂特征并对其断裂机理进行了分析。结果表明，当疲劳温度升高时，S相沿晶界析出量增多，在晶界附近形成TiB颗粒带状分布。复合材料的RM疲劳极限高达307.5 MPa。在相同疲劳强度下，TiB/7050复合材料能承受远大于7050Al合金的疲劳循环。随着温度的升高，复合材料的疲劳性能逐渐下降，与RM和100℃时不同的是，在150℃时需要使用Weibull三参数模型才能获得满意的-曲线。在稳态裂纹扩展阶段的某些位置，疲劳条纹的方向和间距受到晶粒取向、晶界和TiB颗粒带的影响。因此，分析了TiB颗粒、晶界和析出物对疲劳过程的影响，以揭示复合材料的强化机制。