【作者】 张磊；

【导师】 吴志方；

【作者基本信息】 武汉科技大学 ， 材料加工工程， 2018， 硕士

【摘要】 本文采用机械合金化并辅以后续烧结工艺制备了Cu-(10,15,20)wt%Pb纳米相复合结构合金,并对Cu-Pb二元互不溶体系合金在机械合金化过程中过饱和固溶体的形成机制进行了热力学计算。并采用X射线、扫描电子显微镜和差示扫描量热仪等实验手段系统研究了机械合金化制备的Cu-(10,15,20)wt%Pb互不溶体系轴承合金的组织结构和摩擦学性能变化。论文首先综述了轴承合金的研究进展和Cu-Pb互不溶体系轴承合金的制备方法,着重介绍了机械合金化的原理和影响因素,并简述了Cu-Pb互不溶体系轴承合金的硬度和摩擦学性能。采用机械合金化方法在Cu-(10,15)wt%Pb合金中制备了Pb固溶到Cu中的单相纳米晶过饱和固溶体Cu(Pb)。采用机械合金化方法在Cu-20wt%Pb合金中制备了Pb和纳米晶过饱和固溶体Cu(Pb)共存的两相组织。热力学计算结果表明,Cu-Pb二元互不溶体系不具有形成过饱和固溶体的热力学驱动力。Cu-Pb合金经高能球磨形成过饱和固溶体的驱动力主要来源于动力学条件,即位错的存在和晶界能的增加促进了固溶度的扩展。对球磨后的Cu-(10,15,20)wt%Pb合金进行等温烧结处理后,获得了第二相Pb均匀弥散分布在Cu基体上的组织。随烧结温度的升高,MA制备的Cu-(10,15,20)wt%Pb合金的密度、致密度和显微硬度先升高后减小,在623K时,合金的密度、致密度和显微硬度出现最大值。随Pb含量的增加,块体Cu-Pb合金的密度、致密度和显微硬度也增大。随烧结温度的升高,Cu-(10,15,20)wt%Pb合金的磨损量先减小后增大。在623K时,Cu-(10,15,20)wt%Pb合金均表现出最佳抗磨损性能。随Pb含量的增加,Cu-(10,15,20)wt%Pb合金的磨损量逐步减小,耐磨损性逐步提高。与同成分的未经球磨样品相比,球磨后的样品表现出更高的抗承载力及抗磨性。更多还原

【Abstract】 In this thesis,Cu-(10,15,20)wt%Pb nanocomposite alloys were prepared by mechanical alloying assisted with isothermal annealing process.The calculation of thermodynamics about the formation mechanism of the metable structures in Cu-Pb binary immiscible alloys during non-equilibrium process mechanical alloying was carried out.Microstructure and tribological properties of mechanical alloying Cu-(10,15,20)wt%Pb immiscible alloys were systematically investigated by X-ray diffraction,scanning electron microscopy and differential scanning calorimeter.At the beginning of the thesis,A comprehensive review of bearing alloys and the preparation method of Cu-Pb immiscible bearing alloys was carried out.In particular,the principle and influencing factor were summarized.In addition,the hardness and tribology properties of Cu-Pb immiscible bearing alloys were briefly introduced.Single-phase nanocrystalline supersaturated solid solution Cu(Pb)that the Pb was completely dissolved in Cu was observed in Cu-(10,15)wt%Pb alloys prepared by mechanical alloying.The coexistence microstructure of Pb and nanocrystalline supersaturated solid solution Cu(Pb)were observed in Cu-20wt%Pb alloy prepared by mechanical alloying.The thermodynamic calculation result shows that there is no thermodynamic driving force in Cu-Pb binary immiscible system to form supersaturated solid solution,the expanded solid solubility comes from dynamic driving.In other words,the existence of dislocations and the increase of grain boundaries promotes the expansion of solid solubility.The second phase Pb uniformly dispersed in the Cu matrix was obtained in as-milled Cu-(10,15,20)wt%Pb alloys isothermal annealing.With the increase of sintering temperature,the density,relative density and microhardness of MA Cu-(10,15,20)wt%Pb alloys first increases and then decreases,these properties reached the maximum values at 623 K.With the increase of Pb content,the density,relative density and microhardness of Cu-Pb alloy increases.With the increase of annealing temperature,the wearing capacity decreased firstly and then increased,at 623 K,Cu-(10,15,20)wt%Pb alloys showed the best wear resistance capability.With the increase of Pb content,wearing capacity gradually decreased,the wear resistance of the alloy gradually increased.Compared with the ungrinded samples of the same composition,the samples after ball milling showed a higher carrying capacity and anti-friction.更多还原