预氮化+熔覆复合处理制备微纳尺度TiN增强复合涂层

Micro/nano-scale TiN reinforcing composite coatings fabricated by pre-nitriding+cladding treatments

采用预氮化+脉冲激光熔覆复合工艺在TC4钛合金表面成功地制备出了具有微纳尺度TiN增强的Ti-N复合涂层,并与传统激光氮化涂层对比研究了该涂层的组织特征和力学性能。结果表明,所获预氮化复合涂层由TiN相和α′马氏体组成,涂层硬度随引入的固态氮源N含量的增加逐渐增大。对比分析表明,该复合工艺所获涂层的硬度性能与传统激光气体氮化样品基本相当,而在深度方向上其强化效果的维持性更好,并基于数据拟合初步提出了一个用于硬度预测的经验公式。

Composite coatings with micro/nano scale TiN reinforcing phases were successfully fabricated by pre-nitriding＋pulse laser cladding treatments on TC4 substrate surface. A comparative research on microstructures and mechanical properties were carried out between the pre-nitriding＋cladding （PNC） composite coatings and the conventional laser gas nitriding （LGN） samples. The results showed that the PNC composite coatings were composed of TiN and α′ martensite. With the contents of N in powder mixtures augmenting, the hardness increased gradually. Comparative analysis indicated that, the hardness properties of the PNC composite coatings were equivalent with that of LGN samples. In addition, the PNC composite coatings displayed better homogeneity of hardness along depth direction than that of the LGN samples. Based on data fitting, an empirical formula was tentatively developed to estimate the hardness of PNC coatings.