【作者】 韩平；

【导师】 肖福仁； 邹文俊；

【作者基本信息】 燕山大学 ， 材料学， 2013， 博士

【摘要】 金刚石珩磨抛光油石已经在气缸套加工中得到应用，结合剂的结构和性能是决定金刚石珩磨抛光油石珩磨性能的关键。然而，对珩磨油石结合剂的微观结构及对磨损性能的研究很少。因此，根据珩磨加工的特殊要求，研究金刚石珩磨抛光油石结合剂组织结构和性能变化对珩磨性能的影响，是研发金刚石珩磨抛光油石首要解决的关键问题。本文以Cu-Sn结合剂制备珩磨油石，研究Sn含量及合金元素对Cu-Sn结合剂的结构和性能的影响。采用数值模拟，研究Sn含量及合金元素对Cu-Sn结合剂与金刚石之间热应力的影响。根据试验结果和模拟规律，优化结合剂成分并制备成珩磨油石进行珩磨试验。另外，设计树脂金属复合结合剂，对其性能和结构进行初步研究；设计氧化物/Fe基结合剂，研究氧化物对结合剂和金刚石之间热应力的影响，并验证了模拟结果的可靠性。取得主要研究结果如下：随着Sn含量的增加，Cu-Sn结合剂烧结时产生的液相增多，生成硬脆的ε相、δ相和共析体—α+δ增加，烧结后样品的硬度和自锐性提高，抗折强度和热膨胀系数降低。选用Fe、Co和Ni改善Cu75Sn25结合剂的结构和性能，三种合金元素在Cu-Sn结合剂中的固溶程度依次增加。虽然加入合金元素后，Cu75Sn25结合剂的硬度和抗折强度下降，但是Fe的加入提高了自锐性并降低了热膨胀系数；Ni的加入提高了耐高温性能，减少了烧结时液相的流失。采用ANSYS有限元软件模拟计算金刚石和结合剂之间热应力。模拟计算结果显示：随着Sn含量的增加，界面处应力逐渐减小，结合剂对金刚石的把持力增加。Sn含量由15wt.%增加到25wt.%时，界面处应力由895MPa下降到827MPa。Co和Ni加入到Cu75Sn25后，界面处的应力分别提高到1055MPa和1091MPa；Fe加入到Cu75Sn25后，界面处的应力降低到753MPa。制备不同硬度的Cu-Sn-Fe-Ni结合剂金刚石珩磨油石，在格林珩磨机上加工气缸套。硬度为HRB71的结合剂微观结构中含有少量孔隙且磨损量适中，珩磨油石具备良好容屑能力和自锐性，珩磨单个气缸套用时48.0s，每副油石可加工气缸套数量1508个，珩磨加工的气缸套达到欧Ⅴ排放标准。选用Cu65Zn20Ag15和耐热酚醛树脂为原料；以球磨方式提高Cu65Zn20Ag15粉末活性，降低反应活化能，细化晶粒；采用先固化，再热压烧结的工艺制备Cu-Zn-Ag/酚醛树脂复合结合剂。当树脂的含量为10wt.%，热压烧结温度460℃时，Cu-Zn-Ag/酚醛树脂复合结合剂的抗折强度达到最大（150.7MPa），其强度与Cu65Zn20Ag15相当。树脂和金属的浸润性良好，形成相互交叉的三维网络结构。添加Y₂O₃、La₂O₃、V₂O₅和CeO₂降低Fe基结合剂和金刚石之间的热应力，降低程度依次增加。磨损试验结果表明含Y₂O₃、La₂O₃、V₂O₅和CeO₂的结合剂磨损失重量依次减少，结合剂和金刚石之间的缝隙依次变小。磨损试验结果与有限元模拟的规律一致，验证了有限元模拟结合剂对金刚石把持力的可靠性。更多还原

【Abstract】 The diamond honing and polish stones have been applied in honing cylinder liners.The structures and properties of the bonds in stones determine the honing performance.However, there has been little research in the microstructure and wear mechanism of thestones. According to the special requirements of honing, the primary issue that should besolved in developing the stones is the influence of the changes of the microstructure in thestones on honing performance.In this paper, the Cu-Sn bonds were used as the bonds of stones, and the influence ofthe amount of Sn and alloy elements on the microstructures and properties of Cu-Sn bondswas studied. The residual stresses between bonds and diamonds were simulated with finiteelement software. The influence of the amount of Sn and alloy elements on the residualstress was studied. After that, the optimal bonds were used to make honing stones forhoning experiment. The resin-metal bond was designed, and its microstructures andproperties were studied. The Fe-based bonds with oxides were designed, and the influenceof oxides on the residual stress was studied. And the reliability of the simulation result wasvalidated. Results for this paper are as follows:With increasing the amount of Sn, the amount of brittle phase （ε-phsae, δ-phase andeutectoid α+δ） increased. Therefore, the hardness and self-sharpening properties ofCu-Sn bonds increased, and the transverse rupture strength and coefficients of thermalexpansion of Cu-Sn bonds decreased. Fe, Co and Ni were added in Cu75Sn25forimproving its microstructures and properties, respectively. The solid solubility of Fe, Coand Ni in Cu-Sn bonds increased. After adding Fe, Co and Ni in Cu75Sn25, the hardnessand transverse rupture strength of the samples decreased. The self-sharpening property ofthe sample was improved, and the coefficients of thermal expansion decreased afteradding Fe. The temperature resistance of the sample was improved, and the loss of hightemperature liquid decreased after adding Ni.The residual stress between bond and diamond was simulated by ANSYS. Withincreasing the amount of Sn, the residual stress decreased which indicated the increase ofdiamond retention properties. When the amount of Sn was increased from15wt.%to25 wt.%, the residual stress decreased from895MPa to827MPa. After adding Co and Ni inCu75Sn25, the residual stress increased to1055MPa and1091MPa, respectively. Afteradding Fe in Cu75Sn25, the residual stress decreased to753MPa.The Cu-Sn-Fe-Ni bonds in different hardness were utilized in the diamond honingstones. Honing cylinder liners were carried out on a vertical honing machine （Gehring no.Z800-180）. A few pores in the bond hardness of HRB71were available to absorb themetal chip from the cylinder liner, so better chip accommodation and self-sharpeningproperties were obtained. And the throughput of cylinder liners was1,508and the honingefficiency was48s. The surface quality of honed cylinder liner met with the requirementsof Euro V regulations on vehicles.The low melt temperature alloy of Cu65Zn20Ag15and modified phenolic resin wereutilized in the resin-metal bond. The Cu65Zn20Ag15was prealloyed in ball-milling forreducing its activity and active energy and refining grains. After that, the Cu65Zn20Ag15and modified phenolic resin were cured and hot pressed. When the hot-pressedtemperature is460°C, the transverse rupture strength of the sample reached the maximum（150.7MPa） with10wt.%modified phenolic resin. This strength was close to that ofCu65Zn20Ag15. The resin had good wettability with metal, which formed athree-dimensional network structure.CeO₂, La₂O₃, Y₂O₃, and V₂O₅were added in a Fe-based bond, and residual stressesbetween the diamonds and bonds decreased and the decrement increased in the same order.The weight losses of the bonds follow the order Y₂O₃> La₂O₃> V₂O₅> CeO₂, and thegaps between bonds and diamonds decreased in the same order. Therefore, the reliabilityof the simulation result had been validated.更多还原