The thermomechanical fatigue (TMF) behaviors of spray-deposited SiCp-reinforced Al-Si alloy were investigated in terms of the size of Si particles and the Si content. Thermomechanical fatigue experiments were conducted in the temperature range of 150-400°C. The cyclic response behavior indicated that the continuous cyclic softening was exhibited for all materials, and the increase in SiC particles size and Si content aggravated the softening degree, which was attributed to dislocation generation due to differential thermal contraction at the Al matrix/Si phase interface or Al matrix/SiC particle interface. Meanwhile, the TMF life and stress amplitude of SiCp/Al-7Si composites were greater than those of Al-7Si alloy, and increased with the increasing SiC particle size, which was associated with “load sharing” of the direct strengthening mechanism. The stress amplitude of 4.5μmSiCp/Al-Si composite increased as the Si content increased; however, the influence of Si content on the TMF life was not so significant. The TMF failure mechanism revealed that the crack mainly initiated at the agglomeration of small-particulate SiC and the breakage of large-particulate SiC, and the broken primary Si and the exfoliated eutectic Si accelerated the crack propagation.

中文翻译：

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喷射沉积SiCp/Al-Si复合材料在高速铁路制动盘中的热机械疲劳行为

从Si颗粒的尺寸和Si含量方面研究了喷射沉积SiCp增强Al-Si合金的热机械疲劳（TMF）行为。热机械疲劳实验在150-400°C的温度范围内进行。循环响应行为表明，所有材料均表现出连续循环软化，并且随着 SiC 粒径和 Si 含量的增加，软化程度加剧，这是由于 Al 基体/Si 相界面处因热收缩差引起的位错产生所致。或 Al 基体/SiC 颗粒界面。同时，SiCp/Al-7Si 复合材料的 TMF 寿命和应力幅值大于 Al-7Si 合金，并且随着 SiC 粒径的增加而增加，这与直接强化机制的“负荷分担”有关。4.5μmSiCp/Al-Si复合材料的应力幅值随着Si含量的增加而增加；然而，Si 含量对 TMF 寿命的影响并不那么显着。TMF失效机理表明裂纹主要起源于小颗粒SiC的团聚和大颗粒SiC的破裂，破碎的初生Si和剥离的共晶Si加速了裂纹扩展。