The(Cu−10Sn)−Ni−MoS2 composites,prepared by powder metallurgy,were studied for the effects of Ni-coated MoS2 on the microstructure,mechanical properties and lubricating properties.The mechanism of effects of Ni and Mo...The(Cu−10Sn)−Ni−MoS2 composites,prepared by powder metallurgy,were studied for the effects of Ni-coated MoS2 on the microstructure,mechanical properties and lubricating properties.The mechanism of effects of Ni and MoS2 on the properties of composites was analyzed through a comparative experiment by adding Ni and MoS2 separately.The results show that the nickel wrapping around the MoS2 particles decreases the reaction rate of MoS2 with the copper matrix,and greatly improves the bonding of the matrix.The composites with 12 wt.%Ni-coated MoS2(C12)show the optimum performance including the mechanical properties and tribological behaviors.Under oil lubrication conditions,the friction coefficient is 0.0075 with a pressure of 8 MPa and a linear velocity of 0.25 m/s.The average dry friction coefficient,sliding against 40Cr steel disc,is measured to be 0.1769 when the linear velocity and pressure are 0.25 m/s and 4 MPa,respectively.展开更多
High-entropy alloy matrix solid-lubricating composites(HSLCs)are promising anti-wear and friction-reduced materials to meet the demands of complicated engineering applications.Here we present a strat-egy to develop HS...High-entropy alloy matrix solid-lubricating composites(HSLCs)are promising anti-wear and friction-reduced materials to meet the demands of complicated engineering applications.Here we present a strat-egy to develop HSLCs by using the coupled high-entropy phases of(BCC+FCC+L2_(1))with near-equal volume fraction as the matrix material,instead of using the usual single phase-dominated high-entropy phases,which can preserve the intrinsic strength and deformability of the matrix while activating adap-tive wear protection during sliding.This enables a low coefficient of frictions of 0.23-0.31 and wear rates within the order of 10^(-6)-10^(-5) mm^(3) N m^(-1) for the(CrFeNi)_(83)(AlTi)_(17)-Ag-BaF_(2)/CaF_(2) HSLC between room-temperature and 800℃,considerably outperforming the reported HSLCs and conventional alloy matrix solid-lubricating composites.At low and moderate temperatures,the synergistic Ag-BaF_(2)/CaF_(2) lubricat-ing films eliminate the surface stress concentration upon wear,thus suppressing three-body abrasion and surface roughening during the groove multiplication process.At elevated temperatures,the high-entropy composite tribo-layers provide the friction interface with strong and deformable stress shielding,which avoids the oxidative and adhesive wear triggered by the delamination of the tribo-layer.Developing sim-ilar coupled high-entropy matrix phases may open an avenue for further optimization of the tribological properties of the HSLCs.展开更多
基金Projects(51371099,51501091)supported by the National Natural Science Foundation of China。
文摘The(Cu−10Sn)−Ni−MoS2 composites,prepared by powder metallurgy,were studied for the effects of Ni-coated MoS2 on the microstructure,mechanical properties and lubricating properties.The mechanism of effects of Ni and MoS2 on the properties of composites was analyzed through a comparative experiment by adding Ni and MoS2 separately.The results show that the nickel wrapping around the MoS2 particles decreases the reaction rate of MoS2 with the copper matrix,and greatly improves the bonding of the matrix.The composites with 12 wt.%Ni-coated MoS2(C12)show the optimum performance including the mechanical properties and tribological behaviors.Under oil lubrication conditions,the friction coefficient is 0.0075 with a pressure of 8 MPa and a linear velocity of 0.25 m/s.The average dry friction coefficient,sliding against 40Cr steel disc,is measured to be 0.1769 when the linear velocity and pressure are 0.25 m/s and 4 MPa,respectively.
基金supported by the National Natural Science Foundation of China (Nos.52175197 and 51975557)the Outstanding Youth Fund of Gansu Province (No.20JR5RA571)the Youth Innovation Promotion Association CAS (No.2022425).
文摘High-entropy alloy matrix solid-lubricating composites(HSLCs)are promising anti-wear and friction-reduced materials to meet the demands of complicated engineering applications.Here we present a strat-egy to develop HSLCs by using the coupled high-entropy phases of(BCC+FCC+L2_(1))with near-equal volume fraction as the matrix material,instead of using the usual single phase-dominated high-entropy phases,which can preserve the intrinsic strength and deformability of the matrix while activating adap-tive wear protection during sliding.This enables a low coefficient of frictions of 0.23-0.31 and wear rates within the order of 10^(-6)-10^(-5) mm^(3) N m^(-1) for the(CrFeNi)_(83)(AlTi)_(17)-Ag-BaF_(2)/CaF_(2) HSLC between room-temperature and 800℃,considerably outperforming the reported HSLCs and conventional alloy matrix solid-lubricating composites.At low and moderate temperatures,the synergistic Ag-BaF_(2)/CaF_(2) lubricat-ing films eliminate the surface stress concentration upon wear,thus suppressing three-body abrasion and surface roughening during the groove multiplication process.At elevated temperatures,the high-entropy composite tribo-layers provide the friction interface with strong and deformable stress shielding,which avoids the oxidative and adhesive wear triggered by the delamination of the tribo-layer.Developing sim-ilar coupled high-entropy matrix phases may open an avenue for further optimization of the tribological properties of the HSLCs.
