A Y2O3 particle enhanced Ni/TiC composite coating was fabricated in-situ on a TC4 Ti alloy by laser surface cladding. The phase component, microstructure, composition distribution and properties of the composite layer...A Y2O3 particle enhanced Ni/TiC composite coating was fabricated in-situ on a TC4 Ti alloy by laser surface cladding. The phase component, microstructure, composition distribution and properties of the composite layer were investigated. The composite layer has graded microstructures and compositions, due to the fast melting followed by rapid solidification and cooling during laser cladding. The TiC powders are completely dissolved into the melted layer during melting and segregated as fine dendrites when solidified. The size of TiC dendrites decreases with increasing depth. Y2O3 fine particles distribute in the whole clad layer. The Y2O3 particle enhanced Ni/TiC composite layer has a quite uniform hardness along depth with a maximum value of HV1380, which is 4 times higher than the initial hardness. The wear resistance of the Ti alloy is significantly improved after laser cladding due to the high hardness of the composite coating.展开更多
Pure copper plates were coated by Ni-TiC dipulse current plating method. The effects of adding different concentration（ranging from 0.5 g/L to 3.0 g/L） of attapulgite nano particles to the plating bath on the surfac...Pure copper plates were coated by Ni-TiC dipulse current plating method. The effects of adding different concentration（ranging from 0.5 g/L to 3.0 g/L） of attapulgite nano particles to the plating bath on the surface morphology, wear resistance, and oxidation resistance of Ni/TiC/Attapulgite nano-composite coatings were investigated. The experimental results show that the composite coating is flat and compact with adding 3.0 g/L in the bath, and the coating preferred orientation is changed from the planes（111） to（200）. The coefficient of the composite coatings decreases from 0.68 to 0.18 with increasing content of attapulgite in the bath, a mixed mode of adhesive-abrasive wear occurs for all coatings, and the wear mechanism shows a transition from adhesive-abrasive to predominantly abrasive wear mechanism when the concentration of attapulgite is beyond 1.5 g/L in electrolyte. The oxidation resistance of composite coatings is the best prepared when adding attapulgite particles at 0.5 g/L in the bath, the oxide mainly consists of a NiO phase by X-ray analysis.展开更多
采用自蔓延高温燃烧合成反应结合准热等静压技术 (SHS/PHIP)制备了组织连续分布的 Ti C- Ni系梯度功能材料 ,产物的成份分析显示 Ni元素沿厚度方向趋于连续过渡 ,改善了反应前的阶跃式分布。对 Ti C- Ni FGM在制备过程中的残余热应力进...采用自蔓延高温燃烧合成反应结合准热等静压技术 (SHS/PHIP)制备了组织连续分布的 Ti C- Ni系梯度功能材料 ,产物的成份分析显示 Ni元素沿厚度方向趋于连续过渡 ,改善了反应前的阶跃式分布。对 Ti C- Ni FGM在制备过程中的残余热应力进行了计算机有限元分析 ,并与 Ti C- Ni两层直接结合体进行了比较 ,发现 FGM具有明显的热应力缓和效果。展开更多
基金Projects (51101096, 51002093) supported by the National Natural Science Foundation of ChinaProject (1052nm05000) supported by Special Foundation of the Shanghai Science and Technology Commission for Nano-Materials ResearchProject (J51042) supported by Leading Academic Discipline Project of the Shanghai Education Commission, China
文摘A Y2O3 particle enhanced Ni/TiC composite coating was fabricated in-situ on a TC4 Ti alloy by laser surface cladding. The phase component, microstructure, composition distribution and properties of the composite layer were investigated. The composite layer has graded microstructures and compositions, due to the fast melting followed by rapid solidification and cooling during laser cladding. The TiC powders are completely dissolved into the melted layer during melting and segregated as fine dendrites when solidified. The size of TiC dendrites decreases with increasing depth. Y2O3 fine particles distribute in the whole clad layer. The Y2O3 particle enhanced Ni/TiC composite layer has a quite uniform hardness along depth with a maximum value of HV1380, which is 4 times higher than the initial hardness. The wear resistance of the Ti alloy is significantly improved after laser cladding due to the high hardness of the composite coating.
基金Founded by the National Natural Youth Science Fundation of China(51301086)the Scientific Research Fund of Nanjing Institute of Technology Doctoral(N20130222 and CKJB201205)the Nanjing Institute of Technology,China
文摘Pure copper plates were coated by Ni-TiC dipulse current plating method. The effects of adding different concentration（ranging from 0.5 g/L to 3.0 g/L） of attapulgite nano particles to the plating bath on the surface morphology, wear resistance, and oxidation resistance of Ni/TiC/Attapulgite nano-composite coatings were investigated. The experimental results show that the composite coating is flat and compact with adding 3.0 g/L in the bath, and the coating preferred orientation is changed from the planes（111） to（200）. The coefficient of the composite coatings decreases from 0.68 to 0.18 with increasing content of attapulgite in the bath, a mixed mode of adhesive-abrasive wear occurs for all coatings, and the wear mechanism shows a transition from adhesive-abrasive to predominantly abrasive wear mechanism when the concentration of attapulgite is beyond 1.5 g/L in electrolyte. The oxidation resistance of composite coatings is the best prepared when adding attapulgite particles at 0.5 g/L in the bath, the oxide mainly consists of a NiO phase by X-ray analysis.
文摘采用自蔓延高温燃烧合成反应结合准热等静压技术 (SHS/PHIP)制备了组织连续分布的 Ti C- Ni系梯度功能材料 ,产物的成份分析显示 Ni元素沿厚度方向趋于连续过渡 ,改善了反应前的阶跃式分布。对 Ti C- Ni FGM在制备过程中的残余热应力进行了计算机有限元分析 ,并与 Ti C- Ni两层直接结合体进行了比较 ,发现 FGM具有明显的热应力缓和效果。
