The fatigue performance of metal matrix composites (MMCs) is highly related to their surface integrity due to the intensive tool-particle interactions and metallographic alterations of matrix, especially under extreme cutting parameters, which could largely result in surface morphologic defects and subsurface damage on the components. Although the fatigue performance of bulk MMCs has been extensively studied, the influence of machining-induced surface anomalies on the fatigue failure mechanism still needs to be understood. This paper investigates the effect of two distinct surface integrities induced by two cutting regimes (ductile, and semi-brittle regime) on the fatigue performance of MMCs. The ductile and semi-brittle regime were represented by different surface integrities regarding the particle behaviours and their effect on the mechanical and metallographic alterations of matrix materials. In-depth analysis in terms of surface topography, subsurface damage, and residual stresses of the machined workpieces has been carried out before the three-point bending fatigue test. The results showed that the samples machined by finish milling (very low feed – semi-brittle regime) unexpectedly presented lower fatigue lives compared to the rough-milled counterparts (high feed – ductile regime), despite the former displayed compressive residual stress and lower surface roughness. It was found that the particles have pronounced influence on the fatigue performance in two different ways: under low cycle fatigue, the particles were prone to be fractured by the high stress applied (which accelerated the formation of crack initiations and therefore shortened the fatigue life), while under high cycle fatigue, the reinforcement particles were not fractured and instead they could inhibit the crack growth up to some extent. Therefore, fatigue lives of the rough-milled samples (high feed – ductile regime) were enhanced due to the retardation of reinforcement particles.

金属基复合材料（MMCs）的疲劳性能与其表面完整性高度相关，这是由于强烈的工具颗粒相互作用和基体的金相变化，特别是在极端切削参数下，这可能在很大程度上导致表面形貌缺陷和亚表面损伤。成分。尽管大块 MMC 的疲劳性能已得到广泛研究，但加工引起的表面异常对疲劳失效机制的影响仍然需要了解。本文研究了由两种切削方式（韧性和半脆性方式）引起的两种不同的表面完整性对 MMC 疲劳性能的影响。延性和半脆性状态由关于颗粒行为及其对基体材料的机械和金相变化的影响的不同表面完整性表示。在三点弯曲疲劳试验之前，对加工工件的表面形貌、次表面损伤和残余应力进行了深入分析。结果表明，与粗铣削对应物（高进给量 - 延性状态）相比，通过精铣（非常低进给 - 半脆性状态）加工的样品出乎意料地表现出较低的疲劳寿命，尽管前者显示出压缩残余应力和下表面粗糙度。发现颗粒以两种不同的方式对疲劳性能产生显着影响：在低周疲劳下，颗粒在高应力作用下容易发生断裂（加速了裂纹萌生的形成，从而缩短了疲劳寿命），而在高周疲劳下，增强颗粒没有断裂，反而可以抑制裂纹扩展至在某种程度上。因此，由于增强颗粒的延迟，粗磨样品（高进给 - 延展状态）的疲劳寿命得到了提高。