热处理时间对TiN-VC增强Co基合金涂层微观组织和耐磨性能的影响

Effect of Heat Treatment Time on Microstructure and Wear Resistance of TiN-VC Reinforced Co-based Alloy Coating

利用激光熔覆技术在低碳钢表面制备了TiN-VC增强Co基合金涂层,系统研究了热处理时间对合金涂层微观组织和耐磨性能的影响.结果表明:650℃热处理3 h后,合金涂层相组成未发生变化,仍由γ-Co、Cr_(23)C_(6)、σ-FeV、TiN和VC相组成,650℃热处理5 h后,σ-FeV相消失.随着热处理时间增加,合金涂层中短棒状树枝晶和等轴晶数量逐渐增加,组织分布更加均匀;合金涂层的显微硬度先降低后增加,磨损失重先增加后降低.与未热处理的合金涂层相比,650℃热处理5 h后,合金涂层的平均显微硬度被提高了3.75%,磨损失重量被降低了6.0%.热处理后合金涂层的磨损机制均为磨粒磨损.

A TiN-VC reinforced Co-based alloy coating was prepared on mild steel by laser cladding technology,and the effect of heat treatment time on the microstructure and wear resistance of the alloy coating was systematically studied.The results showed that the phase composition of the alloy coating remained unchanged after heat treatment at 650℃for 3 h,but still consisted ofγ-Co,Cr_(23) C_(6),σ-FeV,TiN and VC phases.After heat treatment at 650℃for 5 h,theσ-FeV phase disappeared;the number of short rod-like dendrites and equiaxed crystals in the alloy coating gradually increases,and the structure distribution becomes more uniform.The microhardness of the alloy coating first decreases and then increases,and the wear loss first increases and then decreases.Compared with alloy coatings before heat treatment,the microhardness of the alloy coatings after heat treatment at 650℃for 5 h was improved by 3.75%,and the mass loss was reduced by 6.0%.The wear mechanism of the alloy coating after heat treatment is abrasive wear.