绝热剪切失稳与激光辐照软化协同作用下的金刚石/Ni60复合材料沉积特性及其结合机理研究

Because of its exellent properties such as high hardness, low friction coefficient and high thermal conductivity, diamond is often used as reinforcing particle of wear-resistant metal matrix composite coating. However, diamond particle is apt to graphitization during high temperature process such as laser cladding and has weak bonding force with metal matrix when prepared with low heat input technology such as cold spray. Thus, there is currently no effective method to prepare high hardness metal matrix diamond composite coating which has high bonding strength and no graphitization of diamond..This project intends to use supersonic laser deposition technology to prepare diamond composite coating with hard Ni60 alloy as metal matrix. Through process optimization, successful deposition of diamond composite coating with good interfacial bonding and intact diamond particles would be realized. Through systematically study the synergetic effects of adiabatic shear instability and laser irradiation softening on the microstructure and interfacial bonding behavior, deposition characteristics and bonding mechanism would be revealed, which will provide a theoretical basis for micro-characteristics optimization and property evaluation of other high hardness composite coatings prepared by supersonic laser deposition.

金刚石因其硬度高、摩擦系数小、热导率高等优异性能，常被用于耐磨复合涂层的增强相颗粒，但金刚石颗粒在高热输入的涂层制备技术（如激光熔覆）中容易石墨化，而低热输入的涂层制备技术（如冷喷涂）则存在结合力弱的问题，目前尚无有效方法能够制备无石墨化、高结合强度的以高硬度金属为粘结相的金刚石复合耐磨涂层。.本项目拟采用超音速激光沉积技术制备以高硬度Ni60合金为粘结相的金刚石复合涂层，通过工艺调控，获取优化的工艺参数，实现无石墨化、结合良好的高性能金刚石耐磨复合涂层的制备；通过系统研究绝热剪切失稳和激光辐照软化效应对复合涂层微观结构和界面结合行为的影响规律，揭示高硬度复合材料的沉积特性和结合机理，为超音速激光沉积其他高硬度复合耐磨涂层的微观特性调控和性能评价提供理论依据。

金刚石因其硬度高、摩擦系数小、热导率高等优异性能，常被用于耐磨复合涂层的增强相颗粒，但金刚石颗粒在高热输入的涂层制备技术（如激光熔覆）中容易石墨化，而低热输入的涂层制备技术（如冷喷涂）则存在结合力弱的问题，因此制备无石墨化、高结合强度的以高硬度金属为粘结相的金刚石复合耐磨涂层一直是一个极具挑战的工作。.本项目针对上述金刚石复合涂层制备过程存在的问题，采用超音速激光沉积技术制备了高硬度Ni60合金涂层及其金刚石复合涂层。通过对激光辐照温度、金刚石颗粒尺寸、形貌等工艺的调控，获得了优化的工艺参数，实现无石墨化、结合良好的高性能金刚石耐磨复合涂层的制备，并对金刚石复合涂层的耐磨损性能及其机制进行了研究；通过对超音速激光沉积过程中的绝热剪切失稳和激光辐照软化效应的研究，揭示了复合涂层微观结构和界面结合行为的影响因素，阐明了高硬度复合材料的沉积特性和结合机理，为超音速激光沉积其他高硬度复合耐磨涂层的微观特性调控和性能评价提供理论依据，有望在矿山机械、动力装备、能源化工等关键部件的表面强化和再制造实现推广应用。