摘要
采用激光熔化沉积技术在TC4基体表面制备了不同Ti_(2)AlC含量的梯度复合涂层,通过高温分解形成了TiC/Ti_(2)AlC核壳增强结构,并对激光熔化沉积工艺参数、涂层质量以及梯度复合涂层组织形貌的演变及分布进行了研究。结果表明:随着梯度复合涂层中Ti_(2)AlC含量的增加,原位分解析出的TiC增强相以等轴颗粒状、短棒链条状以及树枝晶状均匀分布于各梯度层中,并通过Al原子的扩散插层反应在TiC边缘形成了以Ti_(2)AlC为壳、TiC为核的TiC/Ti_(2)AlC核壳增强结构,涂层晶粒尺寸逐渐细化。梯度复合涂层硬度呈梯度式增长,表层最高硬度较TC4基体提高约61%。TiC增强相有效提高了涂层强度,梯度复合涂层弹性模量及塑性性能得到提升,室温环境下梯度复合涂层磨损率为8.07×10^(-5) mm^(3)/(N·m),仅为TC4基体的46.38%。
The gradient composite coatings with different Ti_(2)AlC contents were fabricated on TC4 substrate by laser melting deposition,TiC/Ti_(2)AlC core-shell reinforced structure was formed through high-temperature decomposition.The processing parameters,coating quality and the evolution and distribution of the microstructures in these gradient coatings were investigated.The results show that,with the increase of Ti_(2)AlC content in the gradient composite coating,the TiC reinforced phases precipitated in situ are uniformly distributed in each gradient layer in the form of equiaxed particles,short rod chains and dendrites.The TiC/Ti_(2)AlC core-shell reinforced structure with Ti_(2)AlC as shell and TiC as core forms at the edge of TiC through the diffusion intercalation reaction of Al atoms,and the grain size of the coating is gradually refined.The hardness of the gradient composite coating increases in a gradient manner,and the highest hardness of the surface layer is about 61%higher than that of the TC4 substrate.The nanoindentation experiments show that the TiC reinforced phase effectively improves the strength of the coating,and the elastic modulus and plastic properties of the gradient composite coating are improved.At room temperature,the wear rate of the gradient composite coating is 8.07×10^(-5) mm^(3)/(N·m),which is only 46.38% of the TC4 substrate.
作者
黄帅
李长征
莫太骞
张耀
杨辉
傅广
肖华强
HUANG Shuai;LI Changzheng;MO Taiqian;ZHANG Yao;YANG Hui;FU Guang;XIAO Huaqiang(School of Mechanical Engineering,Guizhou University,Guiyang 550025,China;Western Titanium Technologies Co.,Ltd.,Shanxi 710299,China;Guizhou Provincial Key Laboratory of Nuclear Components and Materials Manufacturing Technology,Guizhou Aerospace Xinli Casting and Forging Co.,Ltd.,Zunyi 563000,China)
出处
《中国有色金属学报》
北大核心
2025年第12期4197-4212,共16页
The Chinese Journal of Nonferrous Metals
基金
国家自然科学基金资助项目(52365020,52475329)
贵州省科技计划资助项目([2025]041,BQW[2024]011,ZD[2025]083)。
关键词
激光熔化沉积
梯度涂层
MAX相分解
纳米压痕
laser melting deposition
gradient coating
decomposition of MAX phases
nanoindentation
