TiB2对Ni基合金激光熔覆层组织与性能的影响

Effect of TiB2 on microstructure and properties of Ni-based alloy coating by laser cladding

关键词:  激光熔覆  Ni基合金  TiB₂  金属陶瓷涂层  显微组织

Key words:  laser cladding  Ni-based alloy  TiB₂  metalceramics layers  microstructure

摘要:

采用5kWCO₂激光器在低碳钢表面熔覆Ni基合金层及TiB₂/Ni基合金金属陶瓷涂层,研究了两种涂层的组织、显微硬度以及滑动磨损特性。结果表明,Ni基合金层主要组成相为γ-(Ni,Fe),Cr₂₃C₆等,TiB₂/Ni基合金复合涂层组成相主要有γ-(Ni,Fe),Ni3B,TiB₂和TiC等;Ni基合金层由发达γ-(Ni,Fe)枝晶和其间共晶组织所组成,TiB₂/Ni基合金复合涂层典型组织为等轴固溶体以及其间细小共晶组织;TiB₂对熔覆层的组织有显著的影响,使熔覆层组织细化,并由树枝晶转变为等轴晶;加入TiB₂可显著提高Ni基合金涂层的显微硬度及耐磨性能。

Abstract:

Ni-base alloy and TiB₂/Ni-based alloy metal-ceramics coatings were obtained on low carbon steel surface by 5 kW CO₂ laser.Microstructure, phases, microhardness and sliding wear resistance of the coatings were studied.The results shown that Nibased alloy coating consists of γ-(Ni, Fe), Cr₂₃C₆ etc and TiB₂ Nibased alloy composite coating consists of γ-(Ni, Fe), Ni₃B, TiB₂ and TiC and so on.The Ni-based alloy coating is made up of flourishing γ-(Ni, Fe)dendrite and eutectic structure.Equiaxed solid solution and fine eutectic structure are observed in the TiB₂/Ni-based alloy composite coating.The influence of TiB₂ ceramics on microstructure of coating is prominent that the microstructure of coating is finer and the dendrite crystal gradually becomes equiaxed grain.The microhardness and wear resistance of Ni-based alloy can be improved remarkablely by adding TiB₂.