TiAl合金激光表面原位TiC颗粒增强涂层及高温抗氧化性能

Microstructure Characteristics and Oxidation Resistance Properties of "in-situ" TiC Particle Reinforced Coatings by Laser Surface Alloying

摘要:

以高纯石墨粉和C Nb混合粉末为原料，对Ti-46Al-2Cr-1．5Nb-1V合金进行了激光表面合金化处理，对激光改性层的显微组织以及成分进行了观察与分析，并对该合金原始组织及经C和C Nb激光表面改性层的高温抗氧化性能进行了对比分析研究。结果表明，C和C Nb激光表面合金化处理后，在合金表面均“原位”形成了TiC颗粒，Nb以固溶原子形式存在于表面改性层中，TiC颗粒的大小，形态及分布强烈取决于激光工艺参数；激光表面处理后的合金的抗氧化性能明显高于未经激光处理的铸态组织，而且在石墨粉中掺杂Nb粉，处理后的合金具有最佳的抗氧化性能。

Abstract:

Laser surface alloying with C and C+Nb was used to modify the surface properties of Ti-46Al-2Cr-1.5Nb-lV alloy. The microstructure of the laser alloyed surface layer was studied as function of laser processing parameters. The oxidation resistance properties of the original alloy and the samples with the laser surface treatment with C and C+ Nb at high temperature were investigated. The results indicate that, by laser alloying with with C and C+Nb, the particles of TiC were "in-situ" produced in the laser surface layer. Nb exists in the TiAl matrix as the solute atom. The size, shape and distribution of TiC are strongly dependent on the laser processing parameters. By laser surface alloying with C and C+Nb powders, the oxidation resistance is improved obviously, and the sample alloying with C+Nb exhibits the best oxidation resistance.