钛材表面激光熔覆层制备工艺研究

An investigation on thecladdinglayeron thepuretitanium surfacebylasermelting

  • 摘要: 为提高纯钛材表面硬度,试验采用激光熔覆技术在其表面制备了Ti+B4C熔覆层。通过对比12种不同工艺参数下试样熔覆层的外观,随后选择了可获得良好表面质量熔覆层4种工艺进行进一步对比分析,即当激光功率不小于1050W,B4C粉末含量不低于15%时,熔覆层外观表面光滑、均匀。采用金相显微镜和硬度试验对该4种工艺处理的试件进行微观组织和硬度检测。检测结果显示,当B4C粉末含量为15%时,试件熔覆层与基体结合良好,熔覆层侧硬度随着与界面距离增加而升高,当功率为1200W时,硬度最高达到1240Hv;当B4C含量为20%时,熔覆层与基层之间出现连续的过渡层,硬度检测结果显示该过渡层硬度较低,将影响熔覆层与基体的结合质量。因此采用激光熔覆技术在TA2表面制备高硬度熔覆层的最佳工艺为:激光功率为1200W,B4C含量为15%。

     

    Abstract: In this paper, Ti+B4C cladding layer was prepared on pure Ti surface to improve the surface hardness by laser melting. By comparing the appearance of samples with 12 different process parameters, four laser cladding processes in them were selected for further evaluation. In other words, when the laser power is not less than 1050W and the content of B4C powder is not less than 15%, a smooth and uniform cladding layer could be obtained. Following, microstructure analysis and hardness test were employed to evaluate the quality of the cladding layer. The results show that when the content of B4C powder is 15%, the fusion layer of the specimen is well bonded to the substrate. And the hardness of the cladding layer increases with the distance from the interface. And when the laser power is 1200W, the highest hardness reaches 1240Hv. However, when the B4C content is 20%, a continuous transition layer appears between the cladding layer and the substrate. The hardness test results show that the hardness of the transition layer is low. It would affect the bonding quality. Therefore, the best process for preparing a high hardness cladding layer on the surface of TA2 using laser cladding technology is: laser power is 1200W, and B4C content is 15%.

     

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