The role of molybdenum disulfide (MoS2) as a solid lubricant in iron-based powder metallurgy composites has been extensively investigated. However, current understanding of MoS2-modified Fe–C–Cu-based powder metallurgy composites remains incomplete. Therefore, this study investigates the microstructure evolution, mechanical properties, and tribological performance of Fe–1C–5Cu–xMoS2 composites (x = 1.5, 3, 4.5, and 6) fabricated via cold pressing (600 MPa) and vacuum sintering (1150°C, 60 min) with controlled heating rate (8.5 K/min). Microstructure analysis reveals that increasing MoS2 content promotes FeS phase, Fe3Mo3C phase precipitates, and expansion of pearlitic lamellar spacing but induces severe MoS2 agglomeration. The 3 wt % MoS2 composite achieves peak hardness (303 HV), 20% higher than the base alloy (253 HV), while 1.5 wt % MoS2 yields maximum compressive strength (1005 MPa), surpassing the base alloy by about 200% (336 MPa). The improvement of hardness and compressive strength is attributed to the solid solution strengthening effect of Mo atoms derived from MoS2 decomposition. Furthermore, the 6 wt % MoS2 composite exhibits the lowest coefficient of friction (COF), attributed to the formation of MoS2/FeS lubricating films. However, excessive MoS2 agglomeration degrades mechanical properties.
Wang et al. (Mon,) studied this question.