摘要:Ni25 and Ni25/WC coatings were prepared on the surface of Q235 steel by laser directed energy deposition. The element distribution, microstructure and friction-wear properties of the coatings were comparatively analyzed. The results indicate that the coatings are well formed without crack defects. The incompletely dissolved WC reinforcement particles are uniformly distributed in the coating, while a part of that are decomposed under the action of laser, and the C atoms combine with other elements to form a variety of carbides in the coating. During the crystallization process, more nucleation points are provided, making the coating grain more refine compared with Ni25 coating. A part of WC particles remain intact, which change the wear mechanism of the Ni25/WC coating and significantly improve the wear resistance compared with the Ni25 coating.
关键词:Laser Directed Energy Deposition;Microstructure;Friction and Wear;Wear Mechanism
摘要:The effects of heat treatment on the microstructure and mechanical properties of Ti-6Al-4Valloy fabricated by electron beam melting were investigated.The results indicate that the EBM Ti-6Al-4Valloy mainly consists ofαphase and small amount ofβphase after heat treatment at 800~950℃for 40min.The volume fraction ofβphase is hardly affected by the annealing temperature.Theαlamella is coarsened with the increase of heat treatment temperature,resulting in the decrease of strength and increase of plasticity of EBM Ti-6Al-4Valloy.The residual stress is reduced and the plasticity of the material is improved,leading to the enhanced fracture toughness and fatigue properties.Mechanical properties of EBM Ti-6Al-4Valloy can be improved by heat treatment to achieve a balance between strength and plasticity.
摘要:As the current mainstream human implants, it is of great significance to investigate the corrosion behavior of titanium alloys in various human environments. The characteristics and advantages of different additive manufacturing technologies were reviewed, and the corrosion behavior of titanium alloys prepared by selective laser melting and electron beam melting in different human environments were mainly discussed, such as oral cavity and hard bones, and some specific simulated human environments as well as experimental conclusions were summarized. On this basis, the problems that need to be improved in the applications of additive manufactured titanium alloys in the human environment were proposed, and large-scale applications and prospects were predicted.