激光重熔NiCrBSi+TiN复合涂层及界面组织

在Ti4Al1V合金表面上进行了激光重熔NiCrBSi-TiN涂层试验，利用扫描电镜（SEM）和X射线衍射仪（XRD）等手段对熔覆层的组织进行了分析。探讨了TiN的行为及其对组织的影响，测试了熔覆层显微硬度。结果表明，熔覆层由（Cr-Ni-Fe),TiN，NiB，Cr2Ti，Ti2Ni等相组成。在激光重熔过程中TiN颗粒发生了大量的分解，部分分解而来的[Ti],[N]参与熔池冶金反应，[Ti]与NiCrBSi粉末中的Ni,Cr元素发生反应形成Cr2Ti,Ti2Ni金属间化合物，而[N]在冷却时又以TiN,TiN0.3,TiN0.9三种形式在不同部位原位析出，在结合区与热影响区之间有5-6μm的扩散层，Ni元素在扩散层内有明显的浓度梯度。

Study on Interface Microstructure and Laser Re-melting NiCrBSi+TiN Coating

The re-melting coating of NiCrBSi+TiN metal-ceramic powders sprayed on the surface of Ti6Al4V alloy was performed by CO2 laser. By means of scan electron microscopy (SEM) and X-ray diffraction (XRD), microstructure of the coating was investigated and microhardness was measured. The effect of TiN on microstructure is discussed. The experimental results show that the phase of coating are composed of (Cr-Ni-Fe), TiN, NiB, Cr2Ti, Ti2Ni et al.. The TiN particles are dissolved into [Ti] and [N] during laser heating, intermetallic compound Cr2Ti and Ti2Ni result from some of the [Ti] combining with Ni, Cr, and TiN, TiN0.3, TiN0.9 precipitated during cooling in differ position. Thickness of the diffusion layer is approximately 5～6 μm existing between the dilution zone (DZ) and the heat-affected zone (HAZ), concentration gradient of Ni is distinctness in the diffusion layer.