激光熔覆纳米WC/Ni60涂层水润滑磨损组织变化特征

Structure transition characteristics of nanometer WC/Ni60B composite coatings by laser cladding under the condition of water lubrication wear

采用优化后的激光熔覆工艺参数,以团聚纳米晶WC颗粒为增强相,在45钢表面熔覆上一层纳米WC增强Ni基合金复合涂层。采用SEM、EDS、X-ray等技术手段,对涂层表面磨损前和磨损后的显微组织和元素含量进行了分析研究,得到以下结论:磨损表面在摩擦应力作用下,发生了明显的相变特征,其中涂层中碳化物形成元素的位错扩散发生明显,碳化物球化,同时Ni基合金出现常温蠕变现象,当磨损距离达到8000米时,涂层表面有大量纳米级碳化物脱溶析出。

The Ni matrix composite coatings were made with preferred laser cladding processing parameter on 45 steel samples,which were strengthened by agglomerated micro-grain WC particles and agglomerated nano-grain WC particles.The phase and microstructure of the coatings were measured and studied by SEM,EDS,X-ray,TEM.The conclusions were gotten： effected by friction force,on the wear surface,the dislocation diffusion of carbide elements appear intensively,and the carbide particles globalize,at the same time creep deformation on room temperature emerge in Ni matrix.When the wear distance reach 8000 meters,a large number of nano-carbide precipitate from the coating.