TiN_p／镍基合金复合耐磨涂层的激光熔覆

在４５钢表面用激光束熔覆了ＴｉＮ_ｐ／镍基合金复合耐磨涂层，对涂层的组织和滑动磨损性能进行了分析，并讨论了不同激光工艺参数下涂层稀释度的变化情况。熔覆层由ＴｉＮ颗粒、γ－Ｎｉ初晶以及γ－Ｎｉ＋（Ｆｅ，Ｃｒ）_２３（ＣＢ）_６共晶构成。初晶γ－Ｎｉ中观察到高密度的位错，共晶化合物（Ｆｅ，Ｃｒ）_２３（ＣＢ）_６中出现了大量的层错亚结构，这些特征均使得涂层中的基体相得到了强化。在激光熔覆过程中硬质相ＴｉＮ颗粒边缘发生了部分溶解，冷却过程中重新凝固的ＴｉＮ以细小枝晶状独立形核析出。复合涂层中由于ＴｉＮ颗粒的存在使得涂层硬度显著提高，在摩擦系数不明显变大的前提下耐磨性提高了３倍。

Laser Cladding of a Wear-resistant TiN_p/Ni-base Alloy Composite Coating

A 2 kW CO2 laser was employed to clad a TiNp/Ni-alloy composite coating onsteel 1045.The microstructure and sliding wear property of the cladded layer were analyzed. The dilution of the TiNP-reinfored coating under different laser processingconditions was discussed. The cladded layer exhibits TiN particles,γ-Ni primary dendrites and the eutectics of γ-Ni+(Fe,Cr)23(CB)6 in the interdendritic regions. High density dislocations in γ-Ni primary dendrites and a large amounts of stacking-fault within (Fe,Cr)23(CB)6 phase are obseved. Partial dissolution appearing on the edges of original TiN particulates and their regrowth in the form of independent fine dendrites during resolidification are found in the cladding region. The addition of TiN particulates into Ni-alloy coating greatly improves the wear resistance of the composite coating by increasing the microhardness without distinctly increasing the friction coefficient of the composite coating.